Answers

Subtract 42/90 from 15/84

15/84 - 42/90 is -121/420.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 84 and 90 is 1260
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1260
2. For the 1st fraction, since 84 × 15 = 1260,
   15/84 = 15 × 15/84 × 15 = 225/1260
3. Likewise, for the 2nd fraction, since 90 × 14 = 1260,
   42/90 = 42 × 14/90 × 14 = 588/1260
4. Subtract the two like fractions:
   225/1260 - 588/1260 = 225 - 588/1260 = -363/1260
5. After reducing the fraction, the answer is -121/420

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