Subtract 35/90 from 15/42, Solve 15/42

Subtract 35/90 from 15/42

15/42 - 35/90 is -2/63.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 90 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 42 × 15 = 630,
15/42 = 15 × 15/42 × 15 = 225/630
Likewise, for the 2nd fraction, since 90 × 7 = 630,
35/90 = 35 × 7/90 × 7 = 245/630
Subtract the two like fractions:
225/630 - 245/630 = 225 - 245/630 = -20/630
After reducing the fraction, the answer is -2/63

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