Subtract 80/10 from 70/21, Solve 3 7/21

Subtract 80/10 from 70/21

1^st number: 3 7/21, 2^nd number: 8 0/10

70/21 - 80/10 is -14/3.

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,
70/21 = 70 × 10/21 × 10 = 700/210
Likewise, for the 2nd fraction, since 10 × 21 = 210,
80/10 = 80 × 21/10 × 21 = 1680/210
Subtract the two like fractions:
700/210 - 1680/210 = 700 - 1680/210 = -980/210
After reducing the fraction, the answer is -14/3

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