Subtract 40/90 from 7/21
7/21 - 40/90 is -1/9.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 21 × 30 = 630,
7/21 = 7 × 30/21 × 30 = 210/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
40/90 = 40 × 7/90 × 7 = 280/630 - Subtract the two like fractions:
210/630 - 280/630 = 210 - 280/630 = -70/630 - After reducing the fraction, the answer is -1/9
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