Subtract 20/21 from 12/42
12/42 - 20/21 is -2/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
12/42 = 12 × 1/42 × 1 = 12/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
20/21 = 20 × 2/21 × 2 = 40/42 - Subtract the two like fractions:
12/42 - 40/42 = 12 - 40/42 = -28/42 - After reducing the fraction, the answer is -2/3
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