Answers

Subtract 15/7 from 18/21

1^st number: 18/21, 2^nd number: 2 1/7

18/21 - 15/7 is -9/7.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 7 is 21
   
   Next, find the equivalent fraction of both fractional numbers with denominator 21
2. For the 1st fraction, since 21 × 1 = 21,
   18/21 = 18 × 1/21 × 1 = 18/21
3. Likewise, for the 2nd fraction, since 7 × 3 = 21,
   15/7 = 15 × 3/7 × 3 = 45/21
4. Subtract the two like fractions:
   18/21 - 45/21 = 18 - 45/21 = -27/21
5. After reducing the fraction, the answer is -9/7

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