Subtract 63/42 from 20/30, Solve 20/30

Subtract 63/42 from 20/30

1^st number: 20/30, 2^nd number: 1 21/42

20/30 - 63/42 is -5/6.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 42 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 42 × 5 = 210,
63/42 = 63 × 5/42 × 5 = 315/210
Subtract the two like fractions:
140/210 - 315/210 = 140 - 315/210 = -175/210
After reducing the fraction, the answer is -5/6

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