The Changing Size of Toilet Paper - A Math Dilemma!

Which Roll is Today's Product?

Consumer’s Report featured an article about the number games of toilet paper. (Sounds like math to me!) Since I thought the article was interesting, I mentioned it to my husband who, being a science teacher, had to investigate. His motto: Never take anyone’s word for it.

So he marched to our bathroom and discovered that our toilet paper was smaller than the holder which had been there since 1989. (Yes, our house is old - like us). There was a little more than 1/2 inch showing on each side of the roll. To further investigate, my husband went to the trusty Internet. There he discovered the following facts.

1)  Toilet paper was first manufactured in 1857.  Before this, corncobs and many other "soft" items were used for this purpose.

Hey Elmer!
Look what's on sale
at Sears!

2)  In the early American west, pages torn from newspapers or magazines were often used as toilet paper. The Sears catalog was commonly used for this purpose and even the Farmer's Almanac had a hole in it so it could be hung on a hook in the outhouse.

3) In 1935, Northern Tissue advertised "splinter free" toilet paper. (Yes, splinter free!)  Early production procedures frequently left splinters embedded in the paper. And you thought cheap toilet paper was rough!

4)  Toilet paper was originally manufactured in the shape of a square, 4.5" by 4.5" which was about the average size of a man's hand.  The square made it handy to fold over a few times, but still be considered acceptable for sanitary use.  Basically, this size was established because it worked, sort of like the 90 foot pitcher's mound or the ten foot basketball rim.

5)  In the last ten years, the size of toilet paper has been reduced because manufacturers are trying to cut costs by trimming the sheet size.  (Try placing one "square" in your hand now, and you will see what I mean.)

6)  Most toilet paper producers have decreased the width of a roll from 4.5 inches to 4.2 inches (or something close to that).

7)  Not only have many manufacturers diminished the size of the square (which is now a rectangle), but they have also placed fewer "squares" on a roll.

8)  Unfortunately, it is not just the width of the roll that has been altered.  The size of the cardboard tube in the middle now has a larger diameter, and that is not something you can easily compare in the store!

9)  Typical sizes of popular brands which I had available to measure:

• Kleenex Cottenelle - Standard: 4.5" x 4.0"
• Angel Soft - Standard:  4.5" x 4.0"
• Quilted Northern:  4.5" x 4.0"

What's really comical (or depressing) is that even though toilet paper is smaller and sometimes thinner and more transparent, it still costs the same as the old size.  It is just like so many other products we purchase.  No longer can we buy three pounds of coffee or a one pound can of beans.  (I noticed the beans because I used them for students to feel how heavy 16 ounces was. They can now weighs 14 ounces!)  Then there is the 1/2 gallon of ice cream which decreased overnight to 1.75 quarts and half gallon containers of Tropicana Orange Juice which suddenly became 59 ounces instead of 64!  But toilet paper?  I never thought they would play the number game with toilet paper.  Is nothing sacred in the world of mathematics?

A Multiplication "Trick" To Know When You Are Multiplying by 11

Knowing how to do math does NOT require magic; although, sometimes working a problem can appear to be done magically.  This week I want to talk about multiplying by eleven. Before I demonstrate the "trick", I have to get on my soap box for just a moment. In my humble opinion, all students should know their times tables through 12 even though the Common Core Standard for third grade says through 10 x 10. Remember, Common Core is the minimum or base line of what is to be learned. In Algebra, I insist that my students know the doubles through 25 x 25 and the square roots of those answers up to 625. It saves so much time when we are working with polynomials.

Now to our our amazing mathematical "trick". Let's look at the problem below which is 231 x 11.

 

First we write the problem vertically. Next, we bring down the number in the ones place which in this case is a one. Now we add the digits in the ones and tens place which is 3 + 1 and get the sum of four which is brought down into the answer.


Moving over to the hundreds place, we add that digit with the digit in the tens place 2 + 3 and get an answer of five which we bring down. Finally, we bring down the digit in the hundreds place which is a two. The answer to 231 x 11 is 2,541.

Now try 452 x 11 in your head. Did you get 4,972? Let's try one more. This time multiply 614 by 11. I'm waiting...... Is your answer 6,754?

Now it is time to make this process a little more difficult. What happens if we have to regroup or carry in one of these multiplication problems?

We will multiply 784 by 11. Notice that we start as we did before by just bringing down the number in the ones place. Next, we add 8 + 4 and get a sum of 12. We write down the 2 but carry or regroup the one. We now add 7 + 8 which is 15 and then add in the 1 we are carrying. That makes 16. We bring down the 6 but carry the 1 over. We have a 7 in the hundreds place, but must add in the one we are carrying to get a sum of 8. Thus our answer is 8,624.

Let's see if you can do these without paper or pencil. 965 x 11 768 x 11 859 x 11 After working the problems in your head, write down your answers and check them with a calculator. Try making up some four and five digit problems because this is a non-threatening way to have your students practice their multiplication facts. Have fun!

Using the Book, Anno's Mysterious Multiplying Jar, to Learn About Factorials

Factorial is a word that mathematicians use to describe a special kind of numerical relationship. Factorials are very simple things. They are just products, indicated by the symbol of an exclamation mark. The factorial function (symbol: !) means to multiply a series of descending natural numbers. For instance, "five factorial" is written as "5!" (a shorthand method) and means 5 × 4 × 3 × 2 × 1 = 120. Factorials are used in determining the numbers of combinations and permutations and in finding probability.

Now all of that may seem above your mathematical head, but let me introduce you to the book Anno's Mysterious Multiplying Jar by Masaichir and Mitsumasa Anno.  It is a story about one jar and what is inside it. Anno begins with the jar, which contains one island, that has two countries, each of which has three mountains. The story continues like this until 10 is reached.  The colorful pictures are arranged within borders on the page as many times as the number of objects being discussed. For instance when four walled kingdoms are introduced, four kingdoms are on the page.

The explanation of 10! in the back of the book is also very helpful. Even if children do not understand the concept being taught, they will certainly appreciate the detailed colored drawings and imaginative story! The book is best for kids who have been introduced to at least basic multiplication facts, but younger kids will enjoy counting and looking at the pictures even if the rest of it is over their heads; so, this book helps with multiplying skills as well as the mathematical concept of factorials.

You might give the students a worksheet to keep track of how many islands, rooms, etc. there are. The final question is how many jars are there. Hopefully there will some students who catch on to the factorial concept, find the pattern and discover the answer! 

Here is an example of how you might use factorials in solving a word problem.  How many different arrangements can be made with the letters from the word MOVE?  Because there are four different letters and four different spaces, this is how you would solve the problem.

____   ____   ____   ____ 

Four Possible Spaces

All four letters could be placed in the first space. Once the first space is filled, only three letters remain to fit in the second space. Once the second space is filled with a letter, two letters remain to write in the third space. Finally, only one letter is left to take the fourth and final space. Hence, the answer is a factorial (4!) = 4 × 3 × 2 × 1 = 24 arrangements.

Try some problems in your classroom. Start with an imaginary character, Cal Q. Late, who is working at an Ice Cream Store called Flavors. A hungry customer orders a triple scoop ice cream cone with Berry, Vanilla, and Bubble Gum ice cream. How many different ways could Cal Q. Late stack the ice cream flavors on top of each other?

You could answer the question by listing all of the possible orders of the three ice cream flavors from top to bottom. (Students could have colored circles of construction paper to physically rearrange.)

• 
  Bubble Gum - Berry - Vanilla
• Bubble Gum - Vanilla - Berry

• Berry - Vanilla - Bubble Gum
• Berry - Bubble Gum - Vanilla

• Vanilla - Berry - Bubble Gum
• Vanilla - Bubble Gum - Strawberry

Or, if we use factorials, we arrive at the answer much faster: 3! = 3 × 2 × 1 = 6

Learning about patterns and the use of factorials will stretch a students' mathematical mind. Why not try a few problems in your classroom? And by all means, check out Anno's Mysterious Multiplying Jar.

Hands-On Math Using FREE Milk Lid Jug Lids

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Start saving milk jug lids because there are countless hands-on math activities you can do in your classroom using this free manipulative. Here are just four of those ideas.

1) Sort the lids by various attributes such as:

• Color
• Snap-on or Twist-on 
• Label or No Label
• Kind of edge (smooth or rough)

2) Let the students grab one handful of lids.

• Ask the students to count the lids.
• See if the students can write that number.

3) Make a pattern using two different colors of lids.

 

• Identify the pattern using letters of the alphabet or numbers. The pattern above would be an A, A, B pattern or a 1, 1, 2 pattern.

• Now ask the students to use more than two colors to make a pattern

• Once more, have the students identify the pattern using alphabet letters or numbers.

4) Decide on a money value for each color of lid. (Example: Red lids are worth a nickel, blue lids are worth a dime, and white lids are worth a penny.) Put all of the lids into a bag and have the students draw out four lids. Have the students add up the total value of these four lids.

• Use play money (coins) to have the students show the value of the lids. 

• Have the students practice writing money as either a part of a dollar or as cents.

• Another idea is to have the students find all the combinations of lids that would equal a nickel or a dime or a quarter.

The resource, Milk Lid Math, contains over 15 hand-on ideas with numerous activities listed under each idea. The activities may be used with a whole group, small groups or as center activities.

A Summer Activity - Cleaning Lawn Furniture with Shaving Cream

Again, I am going to deviate from the subject of math and offer a fun summer activity I do with my grandchildren. It involves a can of shaving cream, cleaning rags and lawn furniture that has set out all winter.

Were you aware that there are many unusual ways to use shaving cream besides using it for shaving? Did you know that you could...

1) Clean jewelry with it? Spray it on your jewelry and use a soft “old” toothbrush to get off the grime. Rinse with water.

2) Give chrome faucets a brilliant shine? Apply the shaving cream to a sponge and rub it on the faucet. Then wipe it off with a damp cloth.

3) Easily remove paint from your hands? Rub the shaving cream onto your hands; then rinse it off with soap and water.

4) Remove carpet stains? Blot the soiled area with a damp sponge and then spray on the shaving cream. Wipe clean with a damp sponge and let the area dry. It will also work on various clothes stains.

5) Clean vinyl lawn furniture? Spray the lawn furniture with the shaving cream and wipe the grubby areas with a damp rag. Rinse when finished.

Item #5 is what I do each summer. Our lawn furniture sets out over the winter on our patio and even though it is covered, it is filthy when summer comes. I always go to the store and purchase the cheapest shaving cream I can find. (Here, Barbasol sells for about $.89 a can. Depending on the number of grandchildren coming over, determines how many cans I purchase. This year, it was three.) No matter their age, this is one activity that they all look forward to because it is messy!

I write the child’s name on their can of shaving cream and then assign them a piece of furniture to clean. When everyone is done scrubbing and wiping, we get out the garden hose to spray off the remaining shaving cream, and frequently we end up spraying each other.

But what happens to the leftover shaving cream? I think the pictures say it all!

A Recipe for a Homemade Frozen Treat for Those Hot Summer Days

June always brings the first day of summer. This year it was on June 21st. I'm not sure where you live, but I live in Kansas, and each day, it gets hotter and hotter! On a hot day, when you have been outside, there is nothing better than an ice cold treat. For years, I have made homemade Popsicles, first for my children and now for my grandchildren. I thought I would share the quick and easy recipe with you. (I know this might be considered the "far side" of math, but recipes do contain measurement and sometimes, even fractions!)

Popsicle Recipe - Will make 18

1 small package of Jello (any flavor)  

Berry Blue is our favorite!

As you can see, four of my grandchildren like the Berry Blue.

1/2 cup sugar
2 cups boiling water
2 cups cold water

Boil the water. Add the boiling water to the sugar and the small package of Jello. Stir until all the Jello is dissolved. This takes about two minutes. Add the cold water and stir again.

Pour into three sets of Tupperware Popsicle Makers. If you don't have these (I'm not sure they are available anymore), use Popsicle molds found in stores. or use ice cube trays.

Place in the freezer until hardened. Eat and enjoy just like my grandchildren do!

Using Bloom's Taxonomy on a Geometry Test

As one of their assignments, my college students are required to create a practice test using pre-selected math vocabulary. This activity prompts them to review, look up definitions and apply the information to create ten good multiple choice questions while at the same time studying and assessing the material. Since I want the questions to be more than Level 1 (Remembering) or Level II (Understanding) of Bloom's Taxonomy, I give them the following handout to help them visualize the different levels.  My students find it to be simple, self explanatory, easy to understand and to the point.

Level I - Remembering


 What is this shape called?



Level II - Understanding

Circle the shape that is a triangle.



Level III - Applying

       Enclose this circle in a square.




Level IV - Analyzing

What specific shapes were used to draw the picture on your right?

Level V - Evaluating

How is the picture on your right like a real truck?  How is it  different?

Level VI - Creating

Create a new picture using five different geometric shapes. (You may use the same shape more than once, but you must use five different geometric shapes.)

As teachers, we are only limited by our imagination as to the activities we ask our students to complete to help them prepare for a test. However, we still need to teach and provide information so the students can complete these types of tasks successfully. With the aid of the above chart, my students create well written practice tests using a variety of levels of Bloom's. When the task is completed, my students have also reviewed and studied for their next math exam. I consider that as time well spent!

FREE

If you would like a copy of the above chart in a similar but more detailed format, it is available on Teachers Pay Teachers as a FREE resource.

Also available is a simple math dictionary. This 30 page math dictionary for students uses easy and clear definitions as well as formulas and examples so that students can learn and understand new math words without difficulty or cumbersome language. Most definitions include diagrams and/or illustrations for the visual learner. Over 300 common math terms are organized alphabetically for quick reference.

Most Countries Use Metrics, but NOT the United States!

Did you know that there are only three nations which do not use the metric system: Myanmar, Liberia and the United States? The U.S. uses two systems of measurement, the customary and the metric. Yes, since our country does use the metric system, we have given more than an inch, but we haven't gone the whole nine yards.

Today, when we shop for groceries, soda is sold in liters. Medicine is sold in milligrams, food nutrition labels are metric, and what about a 100-meter sprint or a 5K race? Still, we are the only industrialized nation in the world that does not conduct business in metric weights and measures. To be or not to be a metric nation has been a question of great consternation for our country for many years.

Here are some reasons why I think our nation should go to the metric system.

1. It's the measurement system 96% of the world uses. 
2. It is much easier to do conversions since it is based on units of ten. Water freezes at zero, not 32°, and it boils at 100, not 212°. 
3. Teaching two measurement systems to children is time consuming and confusing. 
4. It is the "official" language of science and medicine. 
5. Its use is necessary when you travel outside of the United States. 
6. Conversion from customary to metric is often fraught with errors. Because the metric system is a decimal system of weights and measures, it is easy to convert between units. 
7. There are fewer measures to learn. Once you learn the meaning of the prefixes, you can easily convert mass, volume and distance measurements. No further conversion factors need to be memorized except the specific power of 10. For the Customary System you have to remember 5280 feet = 1 mile, 4 quarts = 1 gallon, 3 feet = 1 yard, 16 oz. = 1 pound, etc. 
8. And just think, I would have less clutter in my kitchen since I wouldn’t need liquid and dry measuring cups or teaspoons and tablespoons! All I would need is a scale and liquid measuring cups!

So, while most nations use the metric system, the United States still clings to pounds, inches, and feet. Why do you think Americans refuse to convert? I’d be interested in your perspective and ideas.

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Get ready to gauge your students' proficiency and equip them for success in all things metric using this pre-assessment metric test. This math test is designed to assess your students' pre-existing knowledge of the metric system. Not only will your students gain a deeper understanding of the differences between metric and customary units of measurement, but with the help of visual examples, they will be able to remember those pesky measurements.

Explaining the Difference Between Odd and Even Numbers

Sometimes we think everyone knows the difference between an odd and even number. When I was teaching my remedial math college class, we were learning the divisibility rules, the first of which is that every even number is divided by two. I wrote the number "546" on the board and asked the class if this was an odd or even number. I had one student who disagreed with the group answer of even. I asked him why he thought the number was odd, and he replied, "Because it has a "5" in it. " It was obvious this student got all the way through high school without a clear understanding of odd and even numbers. So the moral to this story is to be sure to discuss the difference between an even and an odd number with your students.

A good definition for an even number is that it can be put into groups of two without any left over, like giving each person a partner. But when you have an odd number of things and put them into groups of two, one will always be left out.

Try this approach. Make your hands into fists and place them side by side as seen in the illustration. Say a number. Now count, and as you count, put up one finger for each number said, alternating between hands, with fingers touching.

For instance, if you said “3”, you would count one, (left pointer fingerup) two, (right pointer finger up and touching the other pointer finger) three, (left middle finger up). Three is an odd number because one finger does not have a partner to touch.

Here is the sequence to use if the number given were "2". Two is an even number because each finger has a partner.

Repeat this several times, giving the students odd as well as even numbers. By always having a concrete visual (their fingers) will help the kinesthetic and visual learner to "see" the odds and evens.

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Activities such as this can be found in a math booklet entitled Number Tiles for The Primary Grades.  It contains 17 different math problem solving activities that extend from simple counting, to even and odd numbers, to greater than or less than to solving addition and subtraction problems.

Mathematics Tips for Parents for Those Long Summer Months

Success in school starts and continues at home, but many parents feel inadequate when it comes to helping their children with math. While parents can usually find time to read a story to their children, thereby instilling a love for books, they are often at a loss as to how to instill a love and appreciation for mathematics.  Like reading, mathematics is a subject that is indeed necessary for functioning adequately in society.  Here are some tips to help you as you work with your child this school year.

Recognize that you make an important difference in your child's education.   Most children develop a sense of numbers way before the "regular" school years.  If you have a young child, take advantage of those early years through activities at home that teach and at the same time are enjoyable.  You might take your child on a counting walk in your neighborhood to count how many trees, shrubs, plants, houses, birds, dogs, etc. you see.  Look for twigs or pine cones or leaves, etc. and have your child count as many as s/he can. Then lay them side by side to compare the length and ask your child, "Which is the longest, which is the shortest? Are there any that are the same length?"

Provide experiences at home that help your child be successful, and seek ways to let children, even very young children, know that they are needed and important.  Cooking is a fun way to do this. Help your child follow the directions on a Kool Aid packet or frozen juice can to make refreshments for the family.  Help your child cut a fruit or vegetable into halves, fourths, thirds, etc. Let them help prepare a meal while asking, "What do you do first? Second? Third?"  or better yet, allow them to measure the ingredients for a recipe.

Children do not need a lot of motivation when it comes to recognizing and learning the value of coins.  You know they are interested when they start bugging you for money.  However, it is not sufficient for children to be able to just recognize coins, they must also know the value of these coins.  The best way to accomplish this is to use real money.  You might show your child two or more coins and have him/her tell you the total value of the coins.  Or hold up a coin.  After your child identifies it, discuss what the coin would buy at the store.  When going to the grocery store, give your child his/her own money to buy something.  Have them select an item that costs less than the money you have given them.  You can also do a similar activity by asking them to determine what are the fewest number of coins it would take to pay for the item. Give your child a practical math experience by estimating how long it takes to prepare a meal from start to finish.

Parents' attitudes toward mathematics have an impact on children's attitudes; so, be patient with your child.  A wrong answer on a math test or a homework assignment is not a time for scolding.  It tells you to look further, to ask questions, and to find out what the wrong answer is saying about your child's understanding.  Ask your child to explain how they solved the problem.  Most importantly, relax!  Know that neither you nor the teacher needs to be perfect for your child to learn math.  Remember, one bad math assignment/test will not destroy your child's ability to learn math.

But what if you need some assistance?  Luckily, in today's world, we can find mathematical help at the click of a button.  Below are some great places to go and find outside help if your child is struggling or if you need more information for yourself.

Study Shack is a great place to find or make flashcards, play hangman, do matching activities or crosswords.  It has activities for grades 1-6 as well as addition, multiplication, algebra and geometry.  Cliff's Notes for Math is site that has notes, examples and quizzes for your older children.  The subject areas include Basic Math through Calculus.  There are many on-line math dictionaries.  My favorite is A Math Dictionary for Kids because it includes animation and interactive activities.  Even You Tube is a great resource for students struggling with a concept and needing an alternative way of seeing it. 

Finally, talk about people who use math in their jobs, including builders, architects, engineers, computer professionals, and scientists. Point out that even if your child does not plan to pursue a career in which s/he will use math, learning it is still important because math teaches you how to solve problems and how to think logically. AND we use math everyday!

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Here is another resource that may prove useful. It is a ten page, comprehensive, extensive and wide-ranging list of over 200 hyperlinked Educational website addresses for all subjects.

• Organized by a wide range of subject areas
• Broken down into subcategories (i.e. science, then earth science, ecology, etc.)
• Click on the URL and you are automatically taken to the site.

Different Ways to Write Tally Marks

Tally marks are the quickest way of keeping track of a group of five. One vertical line is made for each of the first four numbers; the fifth number is denoted by a diagonal line drawn across the previous four (i.e., from the top of the first line to the bottom of the fourth line). The diagonal fifth line cancels out the other four vertical lines making the entire set represent five.

Tally marks are also known as hash marks and can be defined in the unary numeral system. (A unary operation in a mathematical system is one element used to yield a single result, in this case a vertical line.) These marks are most useful in counting or tallying ongoing results, such as the score in a game or sport, as no intermediate results need to be erased or discarded. They also make it simple to add up the results by simply counting by 5’s. Here is an illustration of what I mean.

• The value 1 is represented by | tally marks.
• The value 2 is represented by | | tally marks.
• The value 3 is represented by | | | tally marks.
• The value 4 is denoted by |||| tally marks.
• The value five is not denoted by | | | | | tally marks. For the number 5, draw four vertical lines (||||) with a diagonal (\) line through them.

I have seen many interesting ways to teach tally marks to younger children. Many teachers will use Popsicle sticks so that the students have a concrete hands-on way of making tally marks. Some have even tried pretzel sticks although there is a good chance some will disappear during the lesson. 

But have you ever seen these kind of tally marks?

My husband, who teaches science, received this data collection paper from a student. The students were tossing coins marked TT, Tt, and tt to determine different genetic traits and tallying the results. The ones seen above are Japanese tally marks. (The student lived in Japan.) I was fascinated about how they were made so I asked him to have this student show me the sequence of how to draw the marks.

I'm not sure what they mean or why they are made this way, but if you look at the 2nd mark you will notice that it looks like a "T" for two. The fourth mark sort of looks like an "F" for four, but so does the third one. As you can see, each complete 正 character uses 5 strokes; so, a series of 正 would each represent 5, just like the English ones. However, to be honest, I am at a total lost to what this really means; so, I resorted to the internet. Here is what I learned. 

Instead of lines, a certain Kanji character is used. In Japan, this mark reminds people of a sign for “masu” which was originally a square wooden box used to measure rice in Japan during the feudal period. Here is what the tally marks would look like if we compared the two systems.

The successive strokes of 正 () are used in China, Japan and Korea to designate tallies in votes, scores, points, sushi orders, and the like, much as is used in Europe, Africa, Australia and North America. Tallies beyond five are written like this 正 with a line drawn underneath each group of five, followed by the remainder. For example, a tally of twelve is written as 正正丅. 

So the next time your visit Japan or go to a Japenese restaurant to order Sushi, look for the tally marks as the waiter takes your order.

HELP! Many of My College Students Don't Know Why We Call Our Number System Base Ten!

Don't you love tests where you ask a question which you believe everyone will get correct, and then find out it just isn't so?  I gave my algebra college students a pretest to see what they knew and didn't know.  One of the first questions was:  Why is our number system called Base Ten?  This is an extremely important concept as it reveals what they know about place value.  Below are some of the answers I received.

1)  It is called Base Ten because we have ten fingers.  (Yikes! If that is so, should we include our toes as well?)

2)  It is called Base Ten because I think you multiply by ten when you move past the decimal sign.  (Well, sort of.  You do multiply by ten when you move to the left of the decimal sign, going from the ones place, to the tens place, to the hundreds place, etc.)

3)  I think it is called Base Ten because it's something we use everyday.  (Really????)

Enough!  It is called Base Ten because we use ten digits (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9) to write all of the other numbers.  Each digit can have one of ten values: any number from 0 through 9. When the value reaches 9, just before 10, it starts over at zero again.  (Notice the pattern below.)

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.

In addition, each place is worth ten times more than the last. Ten is worth ten times more than 1, and 1,000 is ten times more than 100. The pattern continues infinitely both ways on a number line.

The decimal point allows for the place value to continue in a consistent pattern with numbers smaller than one. As we move to the right of the decimal point, each place is divided by ten to get to the next place value. One hundredth is one tenth divided by ten, and one thousandth is one hundredth divided by ten. The pattern goes on infinitely.

100's, 10's, 1's . 0.1, 0.01, 0.001, 0.0001, 0.00001, etc.

Since all mathematics is based on patterns, this should not be a new revelation. Perhaps on the post-test, my students will omit the fingers and instead rely on patterns to answer the questions!

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Get to know your students better by using this EDITABLE Student Math Information Form. It is an easy and effective way to gather information such as…

• How do your students feel about math?
• What are their interests outside of school?
• What do they hope to learn in your class?
• What other math classes have they taken?

Making Butterflies from Recycled Materials - Earth Day Ideas

When one of my granddaughters was in kindergarten, she came home one day with egg carton caterpillars.  I know most of us have made one of these in our lifetime, but to her, this was the best craft ever!

She told me that her teacher was raising butterflies in her classroom, and soon the butterflies would hatch.  Anticipation and excitement reigned until the day she came out of school telling everyone that one of the butterflies had hatched.  However, much to her chagrin, the teacher was going to let it go.  My granddaughter just couldn't understand why or how her teacher could do that!

But, here is the good part!  She got to make a cocoon out of a toilet paper cylinder.  She covered it by gluing on white cotton balls.  Then she made a butterfly out of tissue paper and a small plastic bag tie.  She put the butterfly inside the cocoon and then pretended to have the butterfly hatch!  This was done over and over and over until the cocoon was no more.  Luckily, I was able to get pictures before both were literally destroyed!

Now, what does all of this have to do with math?  I contemplated all the ways to use recycled products to make items for the classroom.  Thus Trash to Treasure was created. It is full of art ideas, fun and engaging mini-lessons as well as cute and easy-to-construct crafts all made from recycled or common, everyday items.

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Find out more than 14 ways to use milk lids for math. Did you know that you can practice math facts using clear plastic containers? Learn how to take two plastic plates and turn them into angle makers. How about using two plastic beverage lids to make card holders for kindergartners or for those whose hands are disabled? Discover ten ways to use carpet squares as well as nine ways to use old calendars. How about playing hop scotch on old carpet squares? Were you aware that butter tubs can become an indoor recess game to practice addition or multiplication facts? These are just a few of the fun and exciting activities that use recycled items found in this resource entitled Trash to Treasure.

Because these numerous activities vary in difficulty and complexity, they are appropriate for any PreK - 4th grade classroom, and the visual and/or kinesthetic learners will love them.

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Techniques for Remembering the Slope for Vertical and Horizontal Lines

I work in the Math Lab at the community college where I also teach. Last week, I had two College Algebra students who were having difficulty with slope.  They knew the equation y = mx + b, but were unsure when it came to horizontal or vertical lines. By the way, they were using their graphing calculators which I made them put away. (The book said no calculators.) I feel that if they construct the lines themselves, it puts a visual image into their brain much better than if the calculator does it for them. Sure enough, one of the sections in their math books gave the picture of the line from which they had to write the equation. They were amazed that I could just look at a graph and know the slope, give the equation, etc. When I taught high school math, my students couldn't use a graphing calculator until the middle of this particular chapter as I wanted them to physically draw the lines.

First, for those who have no idea what I am talking about, slope is rise over run.  Rise is how far a line goes up, and run is how far a line goes along.  At the right, the line goes up 3 and has a run 5; therefore, the slope is 3/5.  Rise/Run (Rise divided by Run) gives us the slope of the line.

When a line is horizontal, it has no rise, only a run. So the numerator would be zero (for no rise) and the denominator would be a number such as 5 for the run.  0 ÷ 5 = 0  This is true for any horizontal line.

A vertical line is different.  It has rise, but no run; therefore there would always be a number in the numerator, but always a zero in the denominator.  Since we cannot divide by zero, the slope is considered undefined. (I do use rise over run stating that a horizontal line might have 0/5 which is equal to 0 and that a vertical line might have 3/0 is undefined because we can't divide by zero. Our college algebra book uses O/K for okay and K/O for knock out which I like, but I still think the students need to know why.)

I wanted these two students to have a picture that would help them remember the difference.  I thought of a table for the horizontal line and asked them what would happen if the legs of the table were uneven.  They agreed that the table would have slope.  Therefore, the table would have a slope of zero if the legs were even.

I then went blank.  In other words, by creative juices stopped working, and I could not think of a picture that would help them visualize undefined. Since Teachers Pay Teachers has a forum,, I asked my fellow math teachers if they had any ideas.  Here is what some of them came up with.

The Enlightened Elephant suggested using a ski slope. She talks about skiing down a "cliff", which would not be possible (although some students try to argue that they could ski down a vertical cliff) and so the slope is "undefined" because it doesn't make sense to ski down a cliff.  Skiing on a horizontal line is possible so it's slope is zero,  She also talks about uphill (positive slope) and downhill (negative slope). 

Math by Lesley Elisabeth tells her students to use "HOY VUX" (rhymes with 'toy bucks')

             Horizontal - Zero (0) slope - y = ?   

             Vertical - Undefined slope - x = ?

All horizontal lines are y =7 or y = -3 etc., and all vertical lines are x =1 or x = 6, etc. Students forget this so the acronym HOY VUX helps them to remember. Once they've mastered the slope concept in Algebra I, for the rest of the school year, for Algebra II (especially equations of asymptotes - a line that continually approaches a given curve but does not meet it at any finite distance) and even in calculus classes for tangent lines, HOY VUX is just faster and more practical. 

Animated Algebra created a video lesson on the Slope Intercept.  She has a boy skateboard down a negative slope, literally right on the graph line. Karen then shows the same boy taking an escalator up on a line that has a positive slope. Later in the lesson, she rotates the line clockwise, each movement with a click, to show the corresponding slope number to link the line to the slope.  She includes lots of other visual cues to help students focus on and pay attention to the concepts.