Subtract 15/45 from 12/21
12/21 - 15/45 is 5/21.
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,
12/21 = 12 × 15/21 × 15 = 180/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
15/45 = 15 × 7/45 × 7 = 105/315 - Subtract the two like fractions:
180/315 - 105/315 = 180 - 105/315 = 75/315 - After reducing the fraction, the answer is 5/21
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