Subtract 3/81 from 15/21
15/21 - 3/81 is 128/189.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 81 is 567
Next, find the equivalent fraction of both fractional numbers with denominator 567 - For the 1st fraction, since 21 × 27 = 567,
15/21 = 15 × 27/21 × 27 = 405/567 - Likewise, for the 2nd fraction, since 81 × 7 = 567,
3/81 = 3 × 7/81 × 7 = 21/567 - Subtract the two like fractions:
405/567 - 21/567 = 405 - 21/567 = 384/567 - After reducing the fraction, the answer is 128/189
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