Subtract 20/90 from 4/21
4/21 - 20/90 is -2/63.
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,
4/21 = 4 × 30/21 × 30 = 120/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
20/90 = 20 × 7/90 × 7 = 140/630 - Subtract the two like fractions:
120/630 - 140/630 = 120 - 140/630 = -20/630 - After reducing the fraction, the answer is -2/63
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