Answers

Subtract 84/12 from 21/90

1^st number: 21/90, 2^nd number: 7 0/12

21/90 - 84/12 is -203/30.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 12 is 180
   
   Next, find the equivalent fraction of both fractional numbers with denominator 180
2. For the 1st fraction, since 90 × 2 = 180,
   21/90 = 21 × 2/90 × 2 = 42/180
3. Likewise, for the 2nd fraction, since 12 × 15 = 180,
   84/12 = 84 × 15/12 × 15 = 1260/180
4. Subtract the two like fractions:
   42/180 - 1260/180 = 42 - 1260/180 = -1218/180
5. After reducing the fraction, the answer is -203/30

MathStep (Works offline)

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

Related: ⁴²/₉₀-⁸⁴/₁₂ ²¹/₉₀-⁸⁴/₂₄ ⁶³/₉₀-⁸⁴/₁₂ ²¹/₉₀-⁸⁴/₃₆ ²¹/₉₀-⁸⁴/₆₀

Subtract Fractions Calculator