Answers

Subtract 45/84 from 20/90

20/90 - 45/84 is -79/252.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 84 is 1260
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1260
2. For the 1st fraction, since 90 × 14 = 1260,
   20/90 = 20 × 14/90 × 14 = 280/1260
3. Likewise, for the 2nd fraction, since 84 × 15 = 1260,
   45/84 = 45 × 15/84 × 15 = 675/1260
4. Subtract the two like fractions:
   280/1260 - 675/1260 = 280 - 675/1260 = -395/1260
5. After reducing the fraction, the answer is -79/252

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