Answers

Subtract 9/20 from 4/42

4/42 - 9/20 is -149/420.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 42 and 20 is 420
   
   Next, find the equivalent fraction of both fractional numbers with denominator 420
2. For the 1st fraction, since 42 × 10 = 420,
   4/42 = 4 × 10/42 × 10 = 40/420
3. Likewise, for the 2nd fraction, since 20 × 21 = 420,
   9/20 = 9 × 21/20 × 21 = 189/420
4. Subtract the two like fractions:
   40/420 - 189/420 = 40 - 189/420 = -149/420

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