__Please note__: For the trick to work, it must be a two digit number that ends in 5.Suppose we have

**35**

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**.**(This means will be making a square.)

- First, look at the number in the hundred’s place. In this case, it is the “3”.
- Next think of the number that comes directly after 3. That would be “4”.
- Now, in your head, multiply 3 × 4. The answer is 12.
- Finally, multiply 5 × 5 which is 25.
- Place 12 in front of 25 to get the answer. Thirty-five squared is 1,255.
**3 × 4 = 12 5 × 5 = 25****The answer is 1,225.**

This means that we can build a square that is 35 by 35, and it will contain 1,225 squares or have an area of 1225 squares.

Now let's try

**65**

^{2}

**.**

- One more than 6 is 7; so, 6 x 7 is 42.
- Place 42 in front of 25 (5 x 5) and so 65 squared is 4,225.
- 6 × 7 = 42 5 × 5 = 25
- The answer is 4,225.

**1,2**25, we would use the 12. Think of the factors of 12 that are consecutive numbers. In this case, they would be 3 and 4. Use the smaller of the two which, in this case, is 3. Now place a five after it. You now know the square root of 1,225 is 35.

Thirty-five represents the length of one of the sides of a square that contains 1,225 squares.

Now, try some numbers on your own. When you get comfortable with the "trick", try it with your students. They will find out that math can be magical!

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