Subtract 15/24 from 21/12, Solve 1 9/12

Subtract 15/24 from 21/12

1^st number: 1 9/12, 2^nd number: 15/24

21/12 - 15/24 is 9/8.

Find the least common denominator or LCM of the two denominators:
LCM of 12 and 24 is 24

Next, find the equivalent fraction of both fractional numbers with denominator 24
For the 1st fraction, since 12 × 2 = 24,
21/12 = 21 × 2/12 × 2 = 42/24
Likewise, for the 2nd fraction, since 24 × 1 = 24,
15/24 = 15 × 1/24 × 1 = 15/24
Subtract the two like fractions:
42/24 - 15/24 = 42 - 15/24 = 27/24
After reducing the fraction, the answer is 9/8
In mixed form: 11/8

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