Subtract 4/10 from 72/21, Solve 3 9/21

Subtract 4/10 from 72/21

1^st number: 3 9/21, 2^nd number: 4/10

72/21 - 4/10 is 106/35.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 10 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 21 × 10 = 210,
72/21 = 72 × 10/21 × 10 = 720/210
Likewise, for the 2nd fraction, since 10 × 21 = 210,
4/10 = 4 × 21/10 × 21 = 84/210
Subtract the two like fractions:
720/210 - 84/210 = 720 - 84/210 = 636/210
After reducing the fraction, the answer is 106/35
In mixed form: 31/35

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