Subtract 45/21 from 18/30
1st number: 18/30, 2nd number: 2 3/21
18/30 - 45/21 is -54/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 21 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 30 × 7 = 210,
18/30 = 18 × 7/30 × 7 = 126/210 - Likewise, for the 2nd fraction, since 21 × 10 = 210,
45/21 = 45 × 10/21 × 10 = 450/210 - Subtract the two like fractions:
126/210 - 450/210 = 126 - 450/210 = -324/210 - After reducing the fraction, the answer is -54/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/30-45/21 18/30-90/21 18/60-45/21 18/30-45/42 54/30-45/21 18/90-45/21 18/30-45/63 90/30-45/21