Answers

Subtract 21/8 from 21/20

1^st number: 1 1/20, 2^nd number: 2 5/8

21/20 - 21/8 is -63/40.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 20 and 8 is 40
   
   Next, find the equivalent fraction of both fractional numbers with denominator 40
2. For the 1st fraction, since 20 × 2 = 40,
   21/20 = 21 × 2/20 × 2 = 42/40
3. Likewise, for the 2nd fraction, since 8 × 5 = 40,
   21/8 = 21 × 5/8 × 5 = 105/40
4. Subtract the two like fractions:
   42/40 - 105/40 = 42 - 105/40 = -63/40

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