Subtract 21/56 from 21/72
21/72 - 21/56 is -1/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 56 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
21/72 = 21 × 7/72 × 7 = 147/504 - Likewise, for the 2nd fraction, since 56 × 9 = 504,
21/56 = 21 × 9/56 × 9 = 189/504 - Subtract the two like fractions:
147/504 - 189/504 = 147 - 189/504 = -42/504 - After reducing the fraction, the answer is -1/12
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