Answers

Subtract 72/21 from 7/4

1^st number: 1 3/4, 2^nd number: 3 9/21

7/4 - 72/21 is -47/28.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 4 and 21 is 84
   
   Next, find the equivalent fraction of both fractional numbers with denominator 84
2. For the 1st fraction, since 4 × 21 = 84,
   7/4 = 7 × 21/4 × 21 = 147/84
3. Likewise, for the 2nd fraction, since 21 × 4 = 84,
   72/21 = 72 × 4/21 × 4 = 288/84
4. Subtract the two like fractions:
   147/84 - 288/84 = 147 - 288/84 = -141/84
5. After reducing the fraction, the answer is -47/28

MathStep (Works offline)

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

Related: ¹⁴/₄-⁷²/₂₁ ⁷/₈-⁷²/₂₁ ⁷/₄-⁷²/₄₂ ²¹/₄-⁷²/₂₁ ⁷/₁₂-⁷²/₂₁ ⁷/₄-⁷²/₆₃ ³⁵/₄-⁷²/₂₁ ⁷/₂₀-⁷²/₂₁ ⁴⁹/₄-⁷²/₂₁ ⁷/₂₈-⁷²/₂₁

Subtract Fractions Calculator