Answers

Subtract 21/80 from 3/70

3/70 - 21/80 is -123/560.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 70 and 80 is 560
   
   Next, find the equivalent fraction of both fractional numbers with denominator 560
2. For the 1st fraction, since 70 × 8 = 560,
   3/70 = 3 × 8/70 × 8 = 24/560
3. Likewise, for the 2nd fraction, since 80 × 7 = 560,
   21/80 = 21 × 7/80 × 7 = 147/560
4. Subtract the two like fractions:
   24/560 - 147/560 = 24 - 147/560 = -123/560

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