[Kamog]

Here's a trick to calculate square roots of square numbers without a calculator. Keep subtracting odd numbers like this:

1. 64 - 1 = 63
2. 63 - 3 = 60
3. 60 - 5 = 55
4. 55 - 7 = 48
5. 48- 9 = 39
6. 39 - 11 = 28
7. 28 - 13 = 15
8. 15 - 15 = 0

It took 8 steps to get to 0 so the square root of 64 is 8. I don't know why this works.