Unformatted text preview: Compatible numbers Find pair of numbers which are easily combined. 25 x 17 x 4 = 100 x 17 = 1700 Compensation convert the problem to an easier one with the same answer. 99 + 34 = 133 (pg.45) Left to right calculations may be easier 309 + 607 = 900 + 16 = 916 Methods by multiplying and dividing by 4, 5, 8, 9, 10, 25, 100....
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 Spring '10
 Kwon
 Math, Harshad number, Prime number, Mental Math Mental

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