Answers

Subtract 21/81 from 1/63

1/63 - 21/81 is -46/189.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 63 and 81 is 567
   
   Next, find the equivalent fraction of both fractional numbers with denominator 567
2. For the 1st fraction, since 63 × 9 = 567,
   1/63 = 1 × 9/63 × 9 = 9/567
3. Likewise, for the 2nd fraction, since 81 × 7 = 567,
   21/81 = 21 × 7/81 × 7 = 147/567
4. Subtract the two like fractions:
   9/567 - 147/567 = 9 - 147/567 = -138/567
5. After reducing the fraction, the answer is -46/189

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