Subtract 9/35 from 21/42, Solve 21/42

Subtract 9/35 from 21/42

21/42 - 9/35 is 17/70.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 35 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 42 × 5 = 210,
21/42 = 21 × 5/42 × 5 = 105/210
Likewise, for the 2nd fraction, since 35 × 6 = 210,
9/35 = 9 × 6/35 × 6 = 54/210
Subtract the two like fractions:
105/210 - 54/210 = 105 - 54/210 = 51/210
After reducing the fraction, the answer is 17/70

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