Subtract 45/21 from 20/18
1st number: 1 2/18, 2nd number: 2 3/21
20/18 - 45/21 is -65/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 18 and 21 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 18 × 7 = 126,
20/18 = 20 × 7/18 × 7 = 140/126 - Likewise, for the 2nd fraction, since 21 × 6 = 126,
45/21 = 45 × 6/21 × 6 = 270/126 - Subtract the two like fractions:
140/126 - 270/126 = 140 - 270/126 = -130/126 - After reducing the fraction, the answer is -65/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/18-45/21 20/18-90/21 20/36-45/21 20/18-45/42 60/18-45/21 20/54-45/21 20/18-45/63 20/90-45/21