Subtract 12/15 from 18/42
18/42 - 12/15 is -13/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 15 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
18/42 = 18 × 5/42 × 5 = 90/210 - Likewise, for the 2nd fraction, since 15 × 14 = 210,
12/15 = 12 × 14/15 × 14 = 168/210 - Subtract the two like fractions:
90/210 - 168/210 = 90 - 168/210 = -78/210 - After reducing the fraction, the answer is -13/35
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