Add 18/21 and 28/40
18/21 + 28/40 is 109/70.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
18/21 = 18 × 40/21 × 40 = 720/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
28/40 = 28 × 21/40 × 21 = 588/840 - Add the two like fractions:
720/840 + 588/840 = 720 + 588/840 = 1308/840 - 1308/840 simplified gives 109/70
- So, 18/21 + 28/40 = 109/70
In mixed form: 139/70
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