Subtract 54/21 from 9/8, Solve 1 1/8

Subtract 54/21 from 9/8

1^st number: 1 1/8, 2^nd number: 2 12/21

9/8 - 54/21 is -81/56.

Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168

Next, find the equivalent fraction of both fractional numbers with denominator 168
For the 1st fraction, since 8 × 21 = 168,
9/8 = 9 × 21/8 × 21 = 189/168
Likewise, for the 2nd fraction, since 21 × 8 = 168,
54/21 = 54 × 8/21 × 8 = 432/168
Subtract the two like fractions:
189/168 - 432/168 = 189 - 432/168 = -243/168
After reducing the fraction, the answer is -81/56

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