Subtract 20/18 from 14/21, Solve 14/21

Subtract 20/18 from 14/21

1^st number: 14/21, 2^nd number: 1 2/18

14/21 - 20/18 is -4/9.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 21 × 6 = 126,
14/21 = 14 × 6/21 × 6 = 84/126
Likewise, for the 2nd fraction, since 18 × 7 = 126,
20/18 = 20 × 7/18 × 7 = 140/126
Subtract the two like fractions:
84/126 - 140/126 = 84 - 140/126 = -56/126
After reducing the fraction, the answer is -4/9

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