Subtract 20/21 from 6/9
6/9 - 20/21 is -2/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 9 and 21 is 63
Next, find the equivalent fraction of both fractional numbers with denominator 63 - For the 1st fraction, since 9 × 7 = 63,
6/9 = 6 × 7/9 × 7 = 42/63 - Likewise, for the 2nd fraction, since 21 × 3 = 63,
20/21 = 20 × 3/21 × 3 = 60/63 - Subtract the two like fractions:
42/63 - 60/63 = 42 - 60/63 = -18/63 - After reducing the fraction, the answer is -2/7
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