Subtract 30/20 from 6/21, Solve 6/21

Subtract 30/20 from 6/21

1^st number: 6/21, 2^nd number: 1 10/20

6/21 - 30/20 is -17/14.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
6/21 = 6 × 20/21 × 20 = 120/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
30/20 = 30 × 21/20 × 21 = 630/420
Subtract the two like fractions:
120/420 - 630/420 = 120 - 630/420 = -510/420
After reducing the fraction, the answer is -17/14

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