Subtract 3/8 from 21/81
21/81 - 3/8 is -25/216.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 8 is 648
Next, find the equivalent fraction of both fractional numbers with denominator 648 - For the 1st fraction, since 81 × 8 = 648,
21/81 = 21 × 8/81 × 8 = 168/648 - Likewise, for the 2nd fraction, since 8 × 81 = 648,
3/8 = 3 × 81/8 × 81 = 243/648 - Subtract the two like fractions:
168/648 - 243/648 = 168 - 243/648 = -75/648 - After reducing the fraction, the answer is -25/216
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