Subtract 9/7 from 72/20, Solve 3 12/20

Subtract 9/7 from 72/20

1^st number: 3 12/20, 2^nd number: 1 2/7

72/20 - 9/7 is 81/35.

Find the least common denominator or LCM of the two denominators:
LCM of 20 and 7 is 140

Next, find the equivalent fraction of both fractional numbers with denominator 140
For the 1st fraction, since 20 × 7 = 140,
72/20 = 72 × 7/20 × 7 = 504/140
Likewise, for the 2nd fraction, since 7 × 20 = 140,
9/7 = 9 × 20/7 × 20 = 180/140
Subtract the two like fractions:
504/140 - 180/140 = 504 - 180/140 = 324/140
After reducing the fraction, the answer is 81/35
In mixed form: 211/35

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