Subtract 20/7 from 42/21
1st number: 2 0/21, 2nd number: 2 6/7
42/21 - 20/7 is -6/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 7 is 21
Next, find the equivalent fraction of both fractional numbers with denominator 21 - For the 1st fraction, since 21 × 1 = 21,
42/21 = 42 × 1/21 × 1 = 42/21 - Likewise, for the 2nd fraction, since 7 × 3 = 21,
20/7 = 20 × 3/7 × 3 = 60/21 - Subtract the two like fractions:
42/21 - 60/21 = 42 - 60/21 = -18/21 - After reducing the fraction, the answer is -6/7
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