Subtract 18/9 from 72/84, Solve 72/84

Subtract 18/9 from 72/84

1^st number: 72/84, 2^nd number: 2 0/9

72/84 - 18/9 is -8/7.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 9 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 84 × 3 = 252,
72/84 = 72 × 3/84 × 3 = 216/252
Likewise, for the 2nd fraction, since 9 × 28 = 252,
18/9 = 18 × 28/9 × 28 = 504/252
Subtract the two like fractions:
216/252 - 504/252 = 216 - 504/252 = -288/252
After reducing the fraction, the answer is -8/7

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