Subtract 4/20 from 80/21, Solve 3 17/21

Subtract 4/20 from 80/21

1^st number: 3 17/21, 2^nd number: 4/20

80/21 - 4/20 is 379/105.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
80/21 = 80 × 20/21 × 20 = 1600/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
4/20 = 4 × 21/20 × 21 = 84/420
Subtract the two like fractions:
1600/420 - 84/420 = 1600 - 84/420 = 1516/420
After reducing the fraction, the answer is 379/105
In mixed form: 364/105

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