Answers

Subtract 20/21 from 15/8

1^st number: 1 7/8, 2^nd number: 20/21

15/8 - 20/21 is 155/168.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 8 and 21 is 168
   
   Next, find the equivalent fraction of both fractional numbers with denominator 168
2. For the 1st fraction, since 8 × 21 = 168,
   15/8 = 15 × 21/8 × 21 = 315/168
3. Likewise, for the 2nd fraction, since 21 × 8 = 168,
   20/21 = 20 × 8/21 × 8 = 160/168
4. Subtract the two like fractions:
   315/168 - 160/168 = 315 - 160/168 = 155/168

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