Subtract 18/42 from 3/90
3/90 - 18/42 is -83/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 42 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
3/90 = 3 × 7/90 × 7 = 21/630 - Likewise, for the 2nd fraction, since 42 × 15 = 630,
18/42 = 18 × 15/42 × 15 = 270/630 - Subtract the two like fractions:
21/630 - 270/630 = 21 - 270/630 = -249/630 - After reducing the fraction, the answer is -83/210
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/90-18/42 3/90-36/42 3/90-18/84 9/90-18/42 3/90-54/42 15/90-18/42 3/90-90/42 21/90-18/42