Subtract 42/72 from 21/42
21/42 - 42/72 is -1/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 72 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 42 × 12 = 504,
21/42 = 21 × 12/42 × 12 = 252/504 - Likewise, for the 2nd fraction, since 72 × 7 = 504,
42/72 = 42 × 7/72 × 7 = 294/504 - Subtract the two like fractions:
252/504 - 294/504 = 252 - 294/504 = -42/504 - After reducing the fraction, the answer is -1/12
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