Answers

Subtract 63/42 from 81/40

1^st number: 2 1/40, 2^nd number: 1 21/42

81/40 - 63/42 is 21/40.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 40 and 42 is 840
   
   Next, find the equivalent fraction of both fractional numbers with denominator 840
2. For the 1st fraction, since 40 × 21 = 840,
   81/40 = 81 × 21/40 × 21 = 1701/840
3. Likewise, for the 2nd fraction, since 42 × 20 = 840,
   63/42 = 63 × 20/42 × 20 = 1260/840
4. Subtract the two like fractions:
   1701/840 - 1260/840 = 1701 - 1260/840 = 441/840
5. After reducing the fraction, the answer is 21/40

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