Answers

Subtract 16/81 from 21/4

1^st number: 5 1/4, 2^nd number: 16/81

21/4 - 16/81 is 1637/324.

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,
   21/4 = 21 × 81/4 × 81 = 1701/324
3. Likewise, for the 2nd fraction, since 81 × 4 = 324,
   16/81 = 16 × 4/81 × 4 = 64/324
4. Subtract the two like fractions:
   1701/324 - 64/324 = 1701 - 64/324 = 1637/324
5. In mixed form: 517/324

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad

Related: ⁴²/₄-¹⁶/₈₁ ²¹/₄-³²/₈₁ ²¹/₈-¹⁶/₈₁ ⁶³/₄-¹⁶/₈₁ ²¹/₄-⁴⁸/₈₁ ²¹/₁₂-¹⁶/₈₁ ²¹/₄-⁸⁰/₈₁ ²¹/₂₀-¹⁶/₈₁ ²¹/₂₈-¹⁶/₈₁

Subtract Fractions Calculator