Add 21/40 and 3/42
21/40 + 3/42 is 167/280.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 42 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
21/40 = 21 × 21/40 × 21 = 441/840 - Likewise, for the 2nd fraction, since 42 × 20 = 840,
3/42 = 3 × 20/42 × 20 = 60/840 - Add the two like fractions:
441/840 + 60/840 = 441 + 60/840 = 501/840 - 501/840 simplified gives 167/280
- So, 21/40 + 3/42 = 167/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/40+3/42 21/40+6/42 21/80+3/42 21/40+3/84 63/40+3/42 21/40+9/42 21/40+15/42 21/40+21/42