Answers

Subtract 21/8 from 15/81

1^st number: 15/81, 2^nd number: 2 5/8

15/81 - 21/8 is -527/216.

Steps for subtracting fractions

1. 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
2. For the 1st fraction, since 81 × 8 = 648,
   15/81 = 15 × 8/81 × 8 = 120/648
3. Likewise, for the 2nd fraction, since 8 × 81 = 648,
   21/8 = 21 × 81/8 × 81 = 1701/648
4. Subtract the two like fractions:
   120/648 - 1701/648 = 120 - 1701/648 = -1581/648
5. After reducing the fraction, the answer is -527/216

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