Answers

Subtract 20/63 from 42/81

42/81 - 20/63 is 38/189.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 63 is 567
   
   Next, find the equivalent fraction of both fractional numbers with denominator 567
2. For the 1st fraction, since 81 × 7 = 567,
   42/81 = 42 × 7/81 × 7 = 294/567
3. Likewise, for the 2nd fraction, since 63 × 9 = 567,
   20/63 = 20 × 9/63 × 9 = 180/567
4. Subtract the two like fractions:
   294/567 - 180/567 = 294 - 180/567 = 114/567
5. After reducing the fraction, the answer is 38/189

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