Thread: multiplying 2 numbers

523 * 489 using mental math

523 * 500 = 52300 + 52300 + 52300 + 52300 =

11 less groups... sounds complicated. Any other ideas?

Thanks,

Terminator

We may use the identity ( x+a)(x+b) = x^2 + x(a+b) + ab
Let x = 500, a=23 b = -11 and proceed