Answers

Subtract 20/21 from 5/8

5/8 - 20/21 is -55/168.

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,
   5/8 = 5 × 21/8 × 21 = 105/168
3. Likewise, for the 2nd fraction, since 21 × 8 = 168,
   20/21 = 20 × 8/21 × 8 = 160/168
4. Subtract the two like fractions:
   105/168 - 160/168 = 105 - 160/168 = -55/168

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