Subtract 72/5 from 70/21, Solve 3 7/21

Subtract 72/5 from 70/21

1^st number: 3 7/21, 2^nd number: 14 2/5

70/21 - 72/5 is -166/15.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 5 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 21 × 5 = 105,
70/21 = 70 × 5/21 × 5 = 350/105
Likewise, for the 2nd fraction, since 5 × 21 = 105,
72/5 = 72 × 21/5 × 21 = 1512/105
Subtract the two like fractions:
350/105 - 1512/105 = 350 - 1512/105 = -1162/105
After reducing the fraction, the answer is -166/15

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