Answers

Subtract 21/27 from 42/70

42/70 - 21/27 is -8/45.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 70 and 27 is 1890
   
   Next, find the equivalent fraction of both fractional numbers with denominator 1890
2. For the 1st fraction, since 70 × 27 = 1890,
   42/70 = 42 × 27/70 × 27 = 1134/1890
3. Likewise, for the 2nd fraction, since 27 × 70 = 1890,
   21/27 = 21 × 70/27 × 70 = 1470/1890
4. Subtract the two like fractions:
   1134/1890 - 1470/1890 = 1134 - 1470/1890 = -336/1890
5. After reducing the fraction, the answer is -8/45

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