Subtract 45/30 from 81/42, Solve 1 39/42

Subtract 45/30 from 81/42

1^st number: 1 39/42, 2^nd number: 1 15/30

81/42 - 45/30 is 3/7.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 30 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 42 × 5 = 210,
81/42 = 81 × 5/42 × 5 = 405/210
Likewise, for the 2nd fraction, since 30 × 7 = 210,
45/30 = 45 × 7/30 × 7 = 315/210
Subtract the two like fractions:
405/210 - 315/210 = 405 - 315/210 = 90/210
After reducing the fraction, the answer is 3/7

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