Subtract 9/21 from 21/18, Solve 1 3/18

Subtract 9/21 from 21/18

1^st number: 1 3/18, 2^nd number: 9/21

21/18 - 9/21 is 31/42.

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,
21/18 = 21 × 7/18 × 7 = 147/126
Likewise, for the 2nd fraction, since 21 × 6 = 126,
9/21 = 9 × 6/21 × 6 = 54/126
Subtract the two like fractions:
147/126 - 54/126 = 147 - 54/126 = 93/126
After reducing the fraction, the answer is 31/42

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