Answers

Subtract 20/12 from 5/21

1^st number: 5/21, 2^nd number: 1 8/12

5/21 - 20/12 is -10/7.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 12 is 84
   
   Next, find the equivalent fraction of both fractional numbers with denominator 84
2. For the 1st fraction, since 21 × 4 = 84,
   5/21 = 5 × 4/21 × 4 = 20/84
3. Likewise, for the 2nd fraction, since 12 × 7 = 84,
   20/12 = 20 × 7/12 × 7 = 140/84
4. Subtract the two like fractions:
   20/84 - 140/84 = 20 - 140/84 = -120/84
5. After reducing the fraction, the answer is -10/7

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