Subtract 20/21 from 63/90
63/90 - 20/21 is -53/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
63/90 = 63 × 7/90 × 7 = 441/630 - Likewise, for the 2nd fraction, since 21 × 30 = 630,
20/21 = 20 × 30/21 × 30 = 600/630 - Subtract the two like fractions:
441/630 - 600/630 = 441 - 600/630 = -159/630 - After reducing the fraction, the answer is -53/210
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