Answers

Subtract 54/7 from 20/21

1^st number: 20/21, 2^nd number: 7 5/7

20/21 - 54/7 is -142/21.

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,
   20/21 = 20 × 1/21 × 1 = 20/21
3. Likewise, for the 2nd fraction, since 7 × 3 = 21,
   54/7 = 54 × 3/7 × 3 = 162/21
4. Subtract the two like fractions:
   20/21 - 162/21 = 20 - 162/21 = -142/21

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