Subtract 30/21 from 20/35, Solve 20/35

Subtract 30/21 from 20/35

1^st number: 20/35, 2^nd number: 1 9/21

20/35 - 30/21 is -6/7.

Find the least common denominator or LCM of the two denominators:
LCM of 35 and 21 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 35 × 3 = 105,
20/35 = 20 × 3/35 × 3 = 60/105
Likewise, for the 2nd fraction, since 21 × 5 = 105,
30/21 = 30 × 5/21 × 5 = 150/105
Subtract the two like fractions:
60/105 - 150/105 = 60 - 150/105 = -90/105
After reducing the fraction, the answer is -6/7

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