Subtract 80/21 from 60/45, Solve 1 15/45

Subtract 80/21 from 60/45

1^st number: 1 15/45, 2^nd number: 3 17/21

60/45 - 80/21 is -52/21.

Find the least common denominator or LCM of the two denominators:
LCM of 45 and 21 is 315

Next, find the equivalent fraction of both fractional numbers with denominator 315
For the 1st fraction, since 45 × 7 = 315,
60/45 = 60 × 7/45 × 7 = 420/315
Likewise, for the 2nd fraction, since 21 × 15 = 315,
80/21 = 80 × 15/21 × 15 = 1200/315
Subtract the two like fractions:
420/315 - 1200/315 = 420 - 1200/315 = -780/315
After reducing the fraction, the answer is -52/21

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