Answers

Subtract 27/81 from 21/70

21/70 - 27/81 is -1/30.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 70 and 81 is 5670
   
   Next, find the equivalent fraction of both fractional numbers with denominator 5670
2. For the 1st fraction, since 70 × 81 = 5670,
   21/70 = 21 × 81/70 × 81 = 1701/5670
3. Likewise, for the 2nd fraction, since 81 × 70 = 5670,
   27/81 = 27 × 70/81 × 70 = 1890/5670
4. Subtract the two like fractions:
   1701/5670 - 1890/5670 = 1701 - 1890/5670 = -189/5670
5. After reducing the fraction, the answer is -1/30

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