To multiply together 2-digit numbers having the ones digits the same:    ex. 21×41=861

-Multiply the common ones digits of the numbers being multiplied. This yields the ones digit of the answer. There may be a carry figure.   ex 1×1=_ _ 1

-Add the uncommon tens digits of the numbers being multiplied. To this multiply the common ones digit of the number being multiplied. This yields the tens digit of the answer. There may be a carry figure.    ex. (2+4)(1)=_6_

-Multiply the uncommon tens digits of the numbers being multiplied. This yields the hundreds figure of the answer.    ex. 2×4=8 _ _

Prove:    43×63=2709        82×12=984        31×11=341      74×24=1776