Subtract 12/20 from 30/84, Solve 30/84

Subtract 12/20 from 30/84

30/84 - 12/20 is -17/70.

Find the least common denominator or LCM of the two denominators:
LCM of 84 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 84 × 5 = 420,
30/84 = 30 × 5/84 × 5 = 150/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
12/20 = 12 × 21/20 × 21 = 252/420
Subtract the two like fractions:
150/420 - 252/420 = 150 - 252/420 = -102/420
After reducing the fraction, the answer is -17/70

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