How do you know what square numbers are?

Answer 1

Square numbers are number that can be divided equally by the same number. For example:

49 = 7 x 7

Since 49 can be divided 7 groups of, it's the "square" of 7. 7 is it's "square root"

The best way to figure out your squares is to work backward, and learn your multiplication tables really well.

If you know that the squares are 1, 4, 9,16, 25, 36, 49, 64, 81, and 100 up to root 10, then finding out the square roots of larger numbers isn't so hard. The great thing is no matter how many 10's you add, the numbers stay the same. For example:

7 x 7 = 49, but 70 x 70 = 4900, and 700 x 700 = 490,000

(trick: count how many zeros you have total, multiply the non-zero numbers and tack on the zeros at the end!)

If you are faced with a number like 7,396 do some deductive reasoning to get close. 7396 is greater than 6400 (80 x 80) but smaller than 8100 (90 x 90). A little guess and check shows you that 7396 is the square of 86.