Square a 2 Digit Number, for this example 37:
- Look for the nearest 10 boundary
- In this case up 3 from 37 to 40.
- Since you went UP 3 to 40 go DOWN 3 from 37 to 34.
- Now mentally multiply 34x40
- The way I do it is 34x10=340;
- Double it mentally to 680
- Double it again mentally to 1360
- This 1360 is the FIRST interim answer.
- 37 is "3" away from the 10 boundary 40.
- Square this "3" distance from 10 boundary.
- 3x3=9 which is the SECOND interim answer.
- Add the two interim answers to get the final answer.
- Answer: 1360 + 9 = 1369
With practice this can easily be done in your head.
