Subtract 20/45 from 7/21
7/21 - 20/45 is -1/9.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 21 × 15 = 315,
7/21 = 7 × 15/21 × 15 = 105/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
20/45 = 20 × 7/45 × 7 = 140/315 - Subtract the two like fractions:
105/315 - 140/315 = 105 - 140/315 = -35/315 - After reducing the fraction, the answer is -1/9
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