Answers

Subtract 90/40 from 15/81

1^st number: 15/81, 2^nd number: 2 10/40

15/81 - 90/40 is -223/108.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 40 is 3240
   
   Next, find the equivalent fraction of both fractional numbers with denominator 3240
2. For the 1st fraction, since 81 × 40 = 3240,
   15/81 = 15 × 40/81 × 40 = 600/3240
3. Likewise, for the 2nd fraction, since 40 × 81 = 3240,
   90/40 = 90 × 81/40 × 81 = 7290/3240
4. Subtract the two like fractions:
   600/3240 - 7290/3240 = 600 - 7290/3240 = -6690/3240
5. After reducing the fraction, the answer is -223/108

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