Near(ly) Perfect Squares

Perfect squares are great landmarks for Mental Math. Math has changed since 19XX as calculators have changed the way that Math is taught and learned and tested. Increasing Mental Math ability increases confidence, empowerment and self-reliance.

Nearly Perfect Squares
Perfect squares (like 4^2 = 16 and 5^2 = 25) can help people find close facts like 3 x5 and 4 x 6 (answers are both one less than the perfect squares) .
This will work for:
9 x 11 (99) = 1 less than 10^2 (100)
19 x 21 (399) = 1 less than 20^2 (400)
29 x 31 (899) = 1 less than 30^2 (900)
and for any number!!
(x-1)(x+1) = x^2 - 1 always one less than x^2

Somewhat Nearly Perfect Squares
Perfect squares (like 4^2 = 16 and 5^2 = 25) can help people find somewhat close facts like 2 x 6 and 3 x 7 (answers are both four less than the perfect squares) .
This will work for:
8 x 12 (96) = 4 less than 10^2 (100)
18 x 22 (396) = 4 less than 20^2 (400)
28 x 32 (899) = 4 less than 30^2 (900)
and for any number!!
(x-2)(x+3) = x^2 - 4 always four less than x^2