Add 21/84 and 8/40
21/84 + 8/40 is 9/20.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 84 × 10 = 840,
21/84 = 21 × 10/84 × 10 = 210/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
8/40 = 8 × 21/40 × 21 = 168/840 - Add the two like fractions:
210/840 + 168/840 = 210 + 168/840 = 378/840 - 378/840 simplified gives 9/20
- So, 21/84 + 8/40 = 9/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84+8/40 21/84+16/40 21/84+8/80 63/84+8/40 21/84+24/40 21/84+56/40