Subtract 27/7 from 20/30, Solve 20/30

Subtract 27/7 from 20/30

1^st number: 20/30, 2^nd number: 3 6/7

20/30 - 27/7 is -67/21.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 7 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 30 × 7 = 210,
20/30 = 20 × 7/30 × 7 = 140/210
Likewise, for the 2nd fraction, since 7 × 30 = 210,
27/7 = 27 × 30/7 × 30 = 810/210
Subtract the two like fractions:
140/210 - 810/210 = 140 - 810/210 = -670/210
After reducing the fraction, the answer is -67/21

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