Subtract 20/42 from 25/90
25/90 - 20/42 is -25/126.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 42 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
25/90 = 25 × 7/90 × 7 = 175/630 - Likewise, for the 2nd fraction, since 42 × 15 = 630,
20/42 = 20 × 15/42 × 15 = 300/630 - Subtract the two like fractions:
175/630 - 300/630 = 175 - 300/630 = -125/630 - After reducing the fraction, the answer is -25/126
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