Subtract 20/42 from 3/72
3/72 - 20/42 is -73/168.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 42 is 504
Next, find the equivalent fraction of both fractional numbers with denominator 504 - For the 1st fraction, since 72 × 7 = 504,
3/72 = 3 × 7/72 × 7 = 21/504 - Likewise, for the 2nd fraction, since 42 × 12 = 504,
20/42 = 20 × 12/42 × 12 = 240/504 - Subtract the two like fractions:
21/504 - 240/504 = 21 - 240/504 = -219/504 - After reducing the fraction, the answer is -73/168
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