Subtract 80/60 from 18/42, Solve 18/42

Subtract 80/60 from 18/42

1^st number: 18/42, 2^nd number: 1 20/60

18/42 - 80/60 is -19/21.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 60 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 42 × 10 = 420,
18/42 = 18 × 10/42 × 10 = 180/420
Likewise, for the 2nd fraction, since 60 × 7 = 420,
80/60 = 80 × 7/60 × 7 = 560/420
Subtract the two like fractions:
180/420 - 560/420 = 180 - 560/420 = -380/420
After reducing the fraction, the answer is -19/21

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