Subtract 42/84 from 7/15, Solve 7/15

Subtract 42/84 from 7/15

7/15 - 42/84 is -1/30.

Find the least common denominator or LCM of the two denominators:
LCM of 15 and 84 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 15 × 28 = 420,
7/15 = 7 × 28/15 × 28 = 196/420
Likewise, for the 2nd fraction, since 84 × 5 = 420,
42/84 = 42 × 5/84 × 5 = 210/420
Subtract the two like fractions:
196/420 - 210/420 = 196 - 210/420 = -14/420
After reducing the fraction, the answer is -1/30

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