Answers

Subtract 9/4 from 28/21

1^st number: 1 7/21, 2^nd number: 2 1/4

28/21 - 9/4 is -11/12.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 4 is 84
   
   Next, find the equivalent fraction of both fractional numbers with denominator 84
2. For the 1st fraction, since 21 × 4 = 84,
   28/21 = 28 × 4/21 × 4 = 112/84
3. Likewise, for the 2nd fraction, since 4 × 21 = 84,
   9/4 = 9 × 21/4 × 21 = 189/84
4. Subtract the two like fractions:
   112/84 - 189/84 = 112 - 189/84 = -77/84
5. After reducing the fraction, the answer is -11/12

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