Subtract 7/21 from 18/72
18/72 - 7/21 is -1/12.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 21 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
18/72 = 18 × 7/72 × 7 = 126/504 - Likewise, for the 2nd fraction, since 21 × 24 = 504,
7/21 = 7 × 24/21 × 24 = 168/504 - Subtract the two like fractions:
126/504 - 168/504 = 126 - 168/504 = -42/504 - After reducing the fraction, the answer is -1/12
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