Subtract 20/36 from 28/81
28/81 - 20/36 is -17/81.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 36 is 324
Next, find the equivalent fraction of both fractional numbers with denominator 324 - For the 1st fraction, since 81 × 4 = 324,
28/81 = 28 × 4/81 × 4 = 112/324 - Likewise, for the 2nd fraction, since 36 × 9 = 324,
20/36 = 20 × 9/36 × 9 = 180/324 - Subtract the two like fractions:
112/324 - 180/324 = 112 - 180/324 = -68/324 - After reducing the fraction, the answer is -17/81
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