Answers

Subtract 9/81 from 21/49

21/49 - 9/81 is 20/63.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 49 and 81 is 3969
   
   Next, find the equivalent fraction of both fractional numbers with denominator 3969
2. For the 1st fraction, since 49 × 81 = 3969,
   21/49 = 21 × 81/49 × 81 = 1701/3969
3. Likewise, for the 2nd fraction, since 81 × 49 = 3969,
   9/81 = 9 × 49/81 × 49 = 441/3969
4. Subtract the two like fractions:
   1701/3969 - 441/3969 = 1701 - 441/3969 = 1260/3969
5. After reducing the fraction, the answer is 20/63

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