Add 15/30 and 4/21
15/30 + 4/21 is 29/42.
Steps for adding 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,
15/30 = 15 × 7/30 × 7 = 105/210 - Likewise, for the 2nd fraction, since 21 × 10 = 210,
4/21 = 4 × 10/21 × 10 = 40/210 - Add the two like fractions:
105/210 + 40/210 = 105 + 40/210 = 145/210 - 145/210 simplified gives 29/42
- So, 15/30 + 4/21 = 29/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 15/30+8/21 15/60+4/21 15/30+4/42 45/30+4/21 15/30+12/21 15/90+4/21 15/30+4/63 75/30+4/21 15/30+20/21 15/30+28/21