Answers

Subtract 21/81 from 1/4

1/4 - 21/81 is -1/108.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 4 and 81 is 324
   
   Next, find the equivalent fraction of both fractional numbers with denominator 324
2. For the 1st fraction, since 4 × 81 = 324,
   1/4 = 1 × 81/4 × 81 = 81/324
3. Likewise, for the 2nd fraction, since 81 × 4 = 324,
   21/81 = 21 × 4/81 × 4 = 84/324
4. Subtract the two like fractions:
   81/324 - 84/324 = 81 - 84/324 = -3/324
5. After reducing the fraction, the answer is -1/108

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