Answers

Subtract 21/18 from 42/54

1^st number: 42/54, 2^nd number: 1 3/18

42/54 - 21/18 is -7/18.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 54 and 18 is 54
   
   Next, find the equivalent fraction of both fractional numbers with denominator 54
2. For the 1st fraction, since 54 × 1 = 54,
   42/54 = 42 × 1/54 × 1 = 42/54
3. Likewise, for the 2nd fraction, since 18 × 3 = 54,
   21/18 = 21 × 3/18 × 3 = 63/54
4. Subtract the two like fractions:
   42/54 - 63/54 = 42 - 63/54 = -21/54
5. After reducing the fraction, the answer is -7/18

MathStep (Works offline)

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

Related: ⁸⁴/₅₄-²¹/₁₈ ⁴²/₅₄-⁴²/₁₈ ⁴²/₅₄-²¹/₃₆ ⁴²/₅₄-⁶³/₁₈ ⁴²/₅₄-²¹/₅₄ ⁴²/₅₄-²¹/₉₀

Subtract Fractions Calculator