Subtract 40/45 from 20/42
20/42 - 40/45 is -26/63.
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,
40/45 = 40 × 14/45 × 14 = 560/630 - Subtract the two like fractions:
300/630 - 560/630 = 300 - 560/630 = -260/630 - After reducing the fraction, the answer is -26/63
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