Subtract 21/45 from 30/75
30/75 - 21/45 is -1/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 75 and 45 is 225
Next, find the equivalent fraction of both fractional numbers with denominator 225 - For the 1st fraction, since 75 × 3 = 225,
30/75 = 30 × 3/75 × 3 = 90/225 - Likewise, for the 2nd fraction, since 45 × 5 = 225,
21/45 = 21 × 5/45 × 5 = 105/225 - Subtract the two like fractions:
90/225 - 105/225 = 90 - 105/225 = -15/225 - After reducing the fraction, the answer is -1/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/75-21/45 30/75-42/45 30/75-21/90 90/75-21/45 30/75-63/45