Add 21/42 and 75/80
21/42 + 75/80 is 23/16.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 80 is 1680
Next, find the equivalent fraction of both fractional numbers with denominator 1680 - For the 1st fraction, since 42 × 40 = 1680,
21/42 = 21 × 40/42 × 40 = 840/1680 - Likewise, for the 2nd fraction, since 80 × 21 = 1680,
75/80 = 75 × 21/80 × 21 = 1575/1680 - Add the two like fractions:
840/1680 + 1575/1680 = 840 + 1575/1680 = 2415/1680 - 2415/1680 simplified gives 23/16
- So, 21/42 + 75/80 = 23/16
In mixed form: 17/16
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/84+75/80 63/42+75/80