Answers

Subtract 21/20 from 4/81

1^st number: 4/81, 2^nd number: 1 1/20

4/81 - 21/20 is -1621/1620.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 20 is 1620
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1620
2. For the 1st fraction, since 81 × 20 = 1620,
   4/81 = 4 × 20/81 × 20 = 80/1620
3. Likewise, for the 2nd fraction, since 20 × 81 = 1620,
   21/20 = 21 × 81/20 × 81 = 1701/1620
4. Subtract the two like fractions:
   80/1620 - 1701/1620 = 80 - 1701/1620 = -1621/1620

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