Answers

Subtract 42/50 from 21/40

21/40 - 42/50 is -63/200.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 40 and 50 is 200
   
   Next, find the equivalent fraction of both fractional numbers with denominator 200
2. For the 1st fraction, since 40 × 5 = 200,
   21/40 = 21 × 5/40 × 5 = 105/200
3. Likewise, for the 2nd fraction, since 50 × 4 = 200,
   42/50 = 42 × 4/50 × 4 = 168/200
4. Subtract the two like fractions:
   105/200 - 168/200 = 105 - 168/200 = -63/200

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