Subtract 80/21 from 40/36, Solve 1 4/36

Subtract 80/21 from 40/36

1^st number: 1 4/36, 2^nd number: 3 17/21

40/36 - 80/21 is -170/63.

Find the least common denominator or LCM of the two denominators:
LCM of 36 and 21 is 252

Next, find the equivalent fraction of both fractional numbers with denominator 252
For the 1st fraction, since 36 × 7 = 252,
40/36 = 40 × 7/36 × 7 = 280/252
Likewise, for the 2nd fraction, since 21 × 12 = 252,
80/21 = 80 × 12/21 × 12 = 960/252
Subtract the two like fractions:
280/252 - 960/252 = 280 - 960/252 = -680/252
After reducing the fraction, the answer is -170/63

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