Subtract 20/45 from 21/70
21/70 - 20/45 is -13/90.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 45 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 70 × 9 = 630,
21/70 = 21 × 9/70 × 9 = 189/630 - Likewise, for the 2nd fraction, since 45 × 14 = 630,
20/45 = 20 × 14/45 × 14 = 280/630 - Subtract the two like fractions:
189/630 - 280/630 = 189 - 280/630 = -91/630 - After reducing the fraction, the answer is -13/90
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