Subtract 56/18 from 18/21, Solve 18/21

Subtract 56/18 from 18/21

1^st number: 18/21, 2^nd number: 3 2/18

18/21 - 56/18 is -142/63.

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,
18/21 = 18 × 6/21 × 6 = 108/126
Likewise, for the 2nd fraction, since 18 × 7 = 126,
56/18 = 56 × 7/18 × 7 = 392/126
Subtract the two like fractions:
108/126 - 392/126 = 108 - 392/126 = -284/126
After reducing the fraction, the answer is -142/63

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