Answers

Subtract 20/12 from 21/28

1^st number: 21/28, 2^nd number: 1 8/12

21/28 - 20/12 is -11/12.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 28 and 12 is 84
   
   Next, find the equivalent fraction of both fractional numbers with denominator 84
2. For the 1st fraction, since 28 × 3 = 84,
   21/28 = 21 × 3/28 × 3 = 63/84
3. Likewise, for the 2nd fraction, since 12 × 7 = 84,
   20/12 = 20 × 7/12 × 7 = 140/84
4. Subtract the two like fractions:
   63/84 - 140/84 = 63 - 140/84 = -77/84
5. After reducing the fraction, the answer is -11/12

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