Subtract 15/10 from 30/21, Solve 1 9/21

Subtract 15/10 from 30/21

1^st number: 1 9/21, 2^nd number: 1 5/10

30/21 - 15/10 is -1/14.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 10 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 21 × 10 = 210,
30/21 = 30 × 10/21 × 10 = 300/210
Likewise, for the 2nd fraction, since 10 × 21 = 210,
15/10 = 15 × 21/10 × 21 = 315/210
Subtract the two like fractions:
300/210 - 315/210 = 300 - 315/210 = -15/210
After reducing the fraction, the answer is -1/14

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