Answers

Subtract 98/90 from 18/21

1^st number: 18/21, 2^nd number: 1 8/90

18/21 - 98/90 is -73/315.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 90 is 630
   
   Next, find the equivalent fraction of both fractional numbers with denominator 630
2. For the 1st fraction, since 21 × 30 = 630,
   18/21 = 18 × 30/21 × 30 = 540/630
3. Likewise, for the 2nd fraction, since 90 × 7 = 630,
   98/90 = 98 × 7/90 × 7 = 686/630
4. Subtract the two like fractions:
   540/630 - 686/630 = 540 - 686/630 = -146/630
5. After reducing the fraction, the answer is -73/315

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