Subtract 56/18 from 6/21, Solve 6/21

Subtract 56/18 from 6/21

1^st number: 6/21, 2^nd number: 3 2/18

6/21 - 56/18 is -178/63.

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,
6/21 = 6 × 6/21 × 6 = 36/126
Likewise, for the 2nd fraction, since 18 × 7 = 126,
56/18 = 56 × 7/18 × 7 = 392/126
Subtract the two like fractions:
36/126 - 392/126 = 36 - 392/126 = -356/126
After reducing the fraction, the answer is -178/63

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