Answers

Subtract 40/21 from 70/80

1^st number: 70/80, 2^nd number: 1 19/21

70/80 - 40/21 is -173/168.

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,
   70/80 = 70 × 21/80 × 21 = 1470/1680
3. Likewise, for the 2nd fraction, since 21 × 80 = 1680,
   40/21 = 40 × 80/21 × 80 = 3200/1680
4. Subtract the two like fractions:
   1470/1680 - 3200/1680 = 1470 - 3200/1680 = -1730/1680
5. After reducing the fraction, the answer is -173/168

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