Subtract 42/45 from 20/42
20/42 - 42/45 is -16/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 45 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 42 × 15 = 630,
20/42 = 20 × 15/42 × 15 = 300/630 - Likewise, for the 2nd fraction, since 45 × 14 = 630,
42/45 = 42 × 14/45 × 14 = 588/630 - Subtract the two like fractions:
300/630 - 588/630 = 300 - 588/630 = -288/630 - After reducing the fraction, the answer is -16/35
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