Subtract 81/21 from 20/45
1st number: 20/45, 2nd number: 3 18/21
20/45 - 81/21 is -215/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 21 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 45 × 7 = 315,
20/45 = 20 × 7/45 × 7 = 140/315 - Likewise, for the 2nd fraction, since 21 × 15 = 315,
81/21 = 81 × 15/21 × 15 = 1215/315 - Subtract the two like fractions:
140/315 - 1215/315 = 140 - 1215/315 = -1075/315 - After reducing the fraction, the answer is -215/63
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