Subtract 7/21 from 81/42
1st number: 1 39/42, 2nd number: 7/21
81/42 - 7/21 is 67/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
81/42 = 81 × 1/42 × 1 = 81/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
7/21 = 7 × 2/21 × 2 = 14/42 - Subtract the two like fractions:
81/42 - 14/42 = 81 - 14/42 = 67/42 - In mixed form: 125/42
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