Answers

Subtract 21/9 from 18/21

1^st number: 18/21, 2^nd number: 2 3/9

18/21 - 21/9 is -31/21.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 9 is 63
   
   Next, find the equivalent fraction of both fractional numbers with denominator 63
2. For the 1st fraction, since 21 × 3 = 63,
   18/21 = 18 × 3/21 × 3 = 54/63
3. Likewise, for the 2nd fraction, since 9 × 7 = 63,
   21/9 = 21 × 7/9 × 7 = 147/63
4. Subtract the two like fractions:
   54/63 - 147/63 = 54 - 147/63 = -93/63
5. After reducing the fraction, the answer is -31/21

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