Subtract 70/40 from 28/84, Solve 28/84

Subtract 70/40 from 28/84

1^st number: 28/84, 2^nd number: 1 30/40

28/84 - 70/40 is -17/12.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 40 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 84 × 10 = 840,
28/84 = 28 × 10/84 × 10 = 280/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
70/40 = 70 × 21/40 × 21 = 1470/840
Subtract the two like fractions:
280/840 - 1470/840 = 280 - 1470/840 = -1190/840
After reducing the fraction, the answer is -17/12

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