523 * 489 using mental math

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

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

Thanks,

Terminator

Printable View

- Feb 4th 2013, 09:15 AMterminatormultiplying 2 numbers
523 * 489 using mental math

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

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

Thanks,

Terminator - Feb 4th 2013, 09:27 AMibduttRe: multiplying 2 numbers
We may use the identity ( x+a)(x+b) = x^2 + x(a+b) + ab

Let x = 500, a=23 b = -11 and proceed