Subtract 42/84 from 30/72, Solve 30/72

Subtract 42/84 from 30/72

30/72 - 42/84 is -1/12.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 84 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 72 × 7 = 504,
30/72 = 30 × 7/72 × 7 = 210/504
Likewise, for the 2nd fraction, since 84 × 6 = 504,
42/84 = 42 × 6/84 × 6 = 252/504
Subtract the two like fractions:
210/504 - 252/504 = 210 - 252/504 = -42/504
After reducing the fraction, the answer is -1/12

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