Algebra
Squaring numbers in your head | 52 squared = a^2 + 2ab + b^2 = 50*50 + 2(50 x 2) + 2*2 = 2500 + 200 + 4 = 2704 for numbers around 50 take 2500 add/sub 100 x last digit and add last digit squared 55 = 2500 + 500 + 25 = 3525 |
Squaring numbers in your head | 52 squared = a^2 + 2ab + b^2 = 50*50 + 2(50 x 2) + 2*2 = 2500 + 200 + 4 = 2704 for numbers around 50 take 2500 add/sub 100 x last digit and add last digit squared 55 = 2500 + 500 + 25 = 3525 |