Subtract 12/40 from 7/42
7/42 - 12/40 is -2/15.
Steps for subtracting fractions
- 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,
7/42 = 7 × 20/42 × 20 = 140/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
12/40 = 12 × 21/40 × 21 = 252/840 - Subtract the two like fractions:
140/840 - 252/840 = 140 - 252/840 = -112/840 - After reducing the fraction, the answer is -2/15
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