Subtract 81/40 from 70/84, Solve 70/84

Subtract 81/40 from 70/84

1^st number: 70/84, 2^nd number: 2 1/40

70/84 - 81/40 is -143/120.

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,
70/84 = 70 × 10/84 × 10 = 700/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
81/40 = 81 × 21/40 × 21 = 1701/840
Subtract the two like fractions:
700/840 - 1701/840 = 700 - 1701/840 = -1001/840
After reducing the fraction, the answer is -143/120

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