Subtract 84/72 from 28/42, Solve 28/42

Subtract 84/72 from 28/42

1^st number: 28/42, 2^nd number: 1 12/72

28/42 - 84/72 is -1/2.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 72 is 504

Next, find the equivalent fraction of both fractional numbers with denominator 504
For the 1st fraction, since 42 × 12 = 504,
28/42 = 28 × 12/42 × 12 = 336/504
Likewise, for the 2nd fraction, since 72 × 7 = 504,
84/72 = 84 × 7/72 × 7 = 588/504
Subtract the two like fractions:
336/504 - 588/504 = 336 - 588/504 = -252/504
After reducing the fraction, the answer is -1/2

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