Add 84/28 and 90/21
1st number: 3 0/28, 2nd number: 4 6/21
84/28 + 90/21 is 51/7.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
84/28 = 84 × 3/28 × 3 = 252/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
90/21 = 90 × 4/21 × 4 = 360/84 - Add the two like fractions:
252/84 + 360/84 = 252 + 360/84 = 612/84 - 612/84 simplified gives 51/7
- So, 84/28 + 90/21 = 51/7
In mixed form: 72/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/56+90/21 84/28+90/42 84/28+90/63