Subtract 21/30 from 7/42
7/42 - 21/30 is -8/15.
Steps for subtracting fractions
- 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,
7/42 = 7 × 5/42 × 5 = 35/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
21/30 = 21 × 7/30 × 7 = 147/210 - Subtract the two like fractions:
35/210 - 147/210 = 35 - 147/210 = -112/210 - After reducing the fraction, the answer is -8/15
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