523 * 489 using mental math

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

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

Thanks,

Terminator

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- February 4th 2013, 08:15 AMterminatormultiplying 2 numbers
523 * 489 using mental math

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

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

Thanks,

Terminator - February 4th 2013, 08:27 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