Subtract 70/42 from 4/81, Solve 4/81

Subtract 70/42 from 4/81

1^st number: 4/81, 2^nd number: 1 28/42

4/81 - 70/42 is -131/81.

Find the least common denominator or LCM of the two denominators:
LCM of 81 and 42 is 1134

Next, find the equivalent fraction of both fractional numbers with denominator 1134
For the 1st fraction, since 81 × 14 = 1134,
4/81 = 4 × 14/81 × 14 = 56/1134
Likewise, for the 2nd fraction, since 42 × 27 = 1134,
70/42 = 70 × 27/42 × 27 = 1890/1134
Subtract the two like fractions:
56/1134 - 1890/1134 = 56 - 1890/1134 = -1834/1134
After reducing the fraction, the answer is -131/81

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