To multiply together numbers close to and below 100: ex. 96 x 98 = 9408
-Subtract each number being multiplied from 100 and multiply these differences together. This yields the last two digits of the answer. ex. 100 – 96 = 4 100 – 98 =2 4 x 2 =_ _ 08
-Add the differences above and subtract from 100. This yields the first 2 digits of the answer. ex. 4 + 2 = 6 100 – 6 = 94_ _
*An alternate last step: You can take the difference from 100 of one number being multiplied and subtract this from the other number being multiplied (subtract because you are below 100). 96 – 2 and 98 – 4 give the same result as 100 – (2 + 4). Either way is fine.
Try these: 93 x 97 = 9021 94 x 88 = 8272 97 x 97 = 9409
To multiply together numbers close to and above 100: ex. 107 x 102 = 10914
-Follow step one above: 107 – 100 = 7 102 – 100 = 2 7 x 2 =_ _ _14
-Begin step two above, adding the differences, but this time add this to 100. This yields the first three numbers of the answer. ex. (7 + 2) + 100 = 109_ _
Try these: 109 x 111 = 12099 103 x 105 = 10815 112 x 112 = 12544
*An alternate last step: You can take the difference from 100 of one number being multiplied and add it to the other number being multiplied (add because you are above 100). 107+2 and 102+7 give the same result as (7 + 2) + 100. Either way is fine.
