Subtract 10/8 from 21/30, Solve 21/30

Subtract 10/8 from 21/30

1^st number: 21/30, 2^nd number: 1 2/8

21/30 - 10/8 is -11/20.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 8 is 120

Next, find the equivalent fraction of both fractional numbers with denominator 120
For the 1st fraction, since 30 × 4 = 120,
21/30 = 21 × 4/30 × 4 = 84/120
Likewise, for the 2nd fraction, since 8 × 15 = 120,
10/8 = 10 × 15/8 × 15 = 150/120
Subtract the two like fractions:
84/120 - 150/120 = 84 - 150/120 = -66/120
After reducing the fraction, the answer is -11/20

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