Subtract 12/21 from 21/45
21/45 - 12/21 is -11/105.
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,
21/45 = 21 × 7/45 × 7 = 147/315 - Likewise, for the 2nd fraction, since 21 × 15 = 315,
12/21 = 12 × 15/21 × 15 = 180/315 - Subtract the two like fractions:
147/315 - 180/315 = 147 - 180/315 = -33/315 - After reducing the fraction, the answer is -11/105
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