Subtract 9/15 from 21/42
21/42 - 9/15 is -1/10.
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,
21/42 = 21 × 5/42 × 5 = 105/210 - Likewise, for the 2nd fraction, since 15 × 14 = 210,
9/15 = 9 × 14/15 × 14 = 126/210 - Subtract the two like fractions:
105/210 - 126/210 = 105 - 126/210 = -21/210 - After reducing the fraction, the answer is -1/10
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