Answers

Subtract 20/84 from 20/42

20/42 - 20/84 is 5/21.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 84 is 84
   
   Next, find the equivalent fraction of both fractional numbers with denominator 84
2. For the 1st fraction, since 42 × 2 = 84,
   20/42 = 20 × 2/42 × 2 = 40/84
3. Likewise, for the 2nd fraction, since 84 × 1 = 84,
   20/84 = 20 × 1/84 × 1 = 20/84
4. Subtract the two like fractions:
   40/84 - 20/84 = 40 - 20/84 = 20/84
5. After reducing the fraction, the answer is 5/21

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