Answers

Subtract 63/21 from 18/80

1^st number: 18/80, 2^nd number: 3 0/21

18/80 - 63/21 is -111/40.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 80 and 21 is 1680
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1680
2. For the 1st fraction, since 80 × 21 = 1680,
   18/80 = 18 × 21/80 × 21 = 378/1680
3. Likewise, for the 2nd fraction, since 21 × 80 = 1680,
   63/21 = 63 × 80/21 × 80 = 5040/1680
4. Subtract the two like fractions:
   378/1680 - 5040/1680 = 378 - 5040/1680 = -4662/1680
5. After reducing the fraction, the answer is -111/40

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