Subtract 6/7 from 81/30, Solve 2 21/30

Subtract 6/7 from 81/30

1^st number: 2 21/30, 2^nd number: 6/7

81/30 - 6/7 is 129/70.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 7 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 30 × 7 = 210,
81/30 = 81 × 7/30 × 7 = 567/210
Likewise, for the 2nd fraction, since 7 × 30 = 210,
6/7 = 6 × 30/7 × 30 = 180/210
Subtract the two like fractions:
567/210 - 180/210 = 567 - 180/210 = 387/210
After reducing the fraction, the answer is 129/70
In mixed form: 159/70

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