Subtract 80/70 from 30/21, Solve 1 9/21

Subtract 80/70 from 30/21

1^st number: 1 9/21, 2^nd number: 1 10/70

30/21 - 80/70 is 2/7.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 70 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 21 × 10 = 210,
30/21 = 30 × 10/21 × 10 = 300/210
Likewise, for the 2nd fraction, since 70 × 3 = 210,
80/70 = 80 × 3/70 × 3 = 240/210
Subtract the two like fractions:
300/210 - 240/210 = 300 - 240/210 = 60/210
After reducing the fraction, the answer is 2/7

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