Thursday, March 27, 2008

How to square a number ending with 5

This is my first blog writing. Just like to start by sharing a simple mental calculation.

What is 352?

Step 1: The answer will end in 25

Step 2: 1

+ 3(5) Think: add 1 to the first digit; ignore the rest of the number

4

Step 3: 4 x 3 = 12

Think: Multiply the result times the first digit of the original number. This result is the first part of the answer

12 with 25 makes 1225

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