things you learn from infomercials

[greydruid]

For 100 > x > 89 and 100 > y > 89 and x >= y:

xy = (100 - x)(100-y) + 100(x - (100 - y))

Or, to put it in English, if you're multiplying two numbers in the 90s:

96 * 95 = ?

Start by subtract both numbers from 100 to get two differences.

100 - 96 = 4
100 - 95 = 5

Then subtract the larger difference from the larger number.

96 - 5 = 91

Then multiply the two differences together.

4 * 5 = 20

Then put them together and you have your answer:

96 * 95 = 9120