Answers

Subtract 3/7 from 7/21

7/21 - 3/7 is -2/21.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 7 is 21
   
   Next, find the equivalent fraction of both fractional numbers with denominator 21
2. For the 1st fraction, since 21 × 1 = 21,
   7/21 = 7 × 1/21 × 1 = 7/21
3. Likewise, for the 2nd fraction, since 7 × 3 = 21,
   3/7 = 3 × 3/7 × 3 = 9/21
4. Subtract the two like fractions:
   7/21 - 9/21 = 7 - 9/21 = -2/21

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