Subtract 27/21 from 20/18, Solve 1 2/18

Subtract 27/21 from 20/18

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

20/18 - 27/21 is -11/63.

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

Next, find the equivalent fraction of both fractional numbers with denominator 126
For the 1st fraction, since 18 × 7 = 126,
20/18 = 20 × 7/18 × 7 = 140/126
Likewise, for the 2nd fraction, since 21 × 6 = 126,
27/21 = 27 × 6/21 × 6 = 162/126
Subtract the two like fractions:
140/126 - 162/126 = 140 - 162/126 = -22/126
After reducing the fraction, the answer is -11/63

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