We simply need to find a common denominator. The common denominator between the two (LCM/Least common multiple for denominator) is 24.
Now, we multiply the numerators also. We have our new numbers: 2 8/24 for October, 12/24 for November, and 3 9/24 for December. Now, we have to add them together. 2 8/24 + 12/24 = 2 20/24
Now, add the December value to the combined October/November values.
2 20/24 + 3 9/24 = 5 29/24
Now, we need to simplify the fraction.
6 9/24
Answer: 6 3/8 inches of rain occured in the three months.
