Subtract 70/45 from 30/21
1st number: 1 9/21, 2nd number: 1 25/45
30/21 - 70/45 is -8/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315
Next, find the equivalent fraction of both fractional numbers with denominator 315 - For the 1st fraction, since 21 × 15 = 315,
30/21 = 30 × 15/21 × 15 = 450/315 - Likewise, for the 2nd fraction, since 45 × 7 = 315,
70/45 = 70 × 7/45 × 7 = 490/315 - Subtract the two like fractions:
450/315 - 490/315 = 450 - 490/315 = -40/315 - After reducing the fraction, the answer is -8/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/21-70/45 30/42-70/45 30/21-70/90 90/21-70/45 30/63-70/45