Answers

Subtract 21/4 from 18/20

1^st number: 18/20, 2^nd number: 5 1/4

18/20 - 21/4 is -87/20.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 20 and 4 is 20
   
   Next, find the equivalent fraction of both fractional numbers with denominator 20
2. For the 1st fraction, since 20 × 1 = 20,
   18/20 = 18 × 1/20 × 1 = 18/20
3. Likewise, for the 2nd fraction, since 4 × 5 = 20,
   21/4 = 21 × 5/4 × 5 = 105/20
4. Subtract the two like fractions:
   18/20 - 105/20 = 18 - 105/20 = -87/20

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