Subtract 70/40 from 80/42, Solve 1 38/42

Subtract 70/40 from 80/42

1^st number: 1 38/42, 2^nd number: 1 30/40

80/42 - 70/40 is 13/84.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 42 × 20 = 840,
80/42 = 80 × 20/42 × 20 = 1600/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
70/40 = 70 × 21/40 × 21 = 1470/840
Subtract the two like fractions:
1600/840 - 1470/840 = 1600 - 1470/840 = 130/840
After reducing the fraction, the answer is 13/84

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