Answers

Subtract 40/42 from 10/21

10/21 - 40/42 is -10/21.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 42 is 42
   
   Next, find the equivalent fraction of both fractional numbers with denominator 42
2. For the 1st fraction, since 21 × 2 = 42,
   10/21 = 10 × 2/21 × 2 = 20/42
3. Likewise, for the 2nd fraction, since 42 × 1 = 42,
   40/42 = 40 × 1/42 × 1 = 40/42
4. Subtract the two like fractions:
   20/42 - 40/42 = 20 - 40/42 = -20/42
5. After reducing the fraction, the answer is -10/21

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