Subtract 21/42 from 20/15, Solve 1 5/15

Subtract 21/42 from 20/15

1^st number: 1 5/15, 2^nd number: 21/42

20/15 - 21/42 is 5/6.

Find the least common denominator or LCM of the two denominators:
LCM of 15 and 42 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 15 × 14 = 210,
20/15 = 20 × 14/15 × 14 = 280/210
Likewise, for the 2nd fraction, since 42 × 5 = 210,
21/42 = 21 × 5/42 × 5 = 105/210
Subtract the two like fractions:
280/210 - 105/210 = 280 - 105/210 = 175/210
After reducing the fraction, the answer is 5/6

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