Subtract 42/72 from 1/28, Solve 1/28

Subtract 42/72 from 1/28

1/28 - 42/72 is -23/42.

Find the least common denominator or LCM of the two denominators:
LCM of 28 and 72 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 28 × 18 = 504,
1/28 = 1 × 18/28 × 18 = 18/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
42/72 = 42 × 7/72 × 7 = 294/504
Subtract the two like fractions:
18/504 - 294/504 = 18 - 294/504 = -276/504
After reducing the fraction, the answer is -23/42

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