Subtract 18/4 from 21/27, Solve 21/27

Subtract 18/4 from 21/27

1^st number: 21/27, 2^nd number: 4 2/4

21/27 - 18/4 is -67/18.

Find the least common denominator or LCM of the two denominators:
LCM of 27 and 4 is 108

Next, find the equivalent fraction of both fractional numbers with denominator 108
For the 1st fraction, since 27 × 4 = 108,
21/27 = 21 × 4/27 × 4 = 84/108
Likewise, for the 2nd fraction, since 4 × 27 = 108,
18/4 = 18 × 27/4 × 27 = 486/108
Subtract the two like fractions:
84/108 - 486/108 = 84 - 486/108 = -402/108
After reducing the fraction, the answer is -67/18

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