fractions
posted by ttuuffyy .
Annie walked her dog 2 1/4 miles from her house to the dog park and 3/7/8 miles around the park.Then she walked the same distance home.How many miles did she walk in all?

2 2/8 + 3 7/8 = 5 9/8 = 6 1/8 mile
6 1/8 + 6 1/8 = ? 
How did you figure that out.Iam trying to explain to my 4 th grader

When we add or subtract fractions, we must have a common denonimator.
2 1/4 = 2 2/8
When I added the two fractions, I added the whole numbers and the numerators. That is 5 9/8. But since 9/8 is larger than 1, I simplified the fraction to 6 1/8.
Which part doesn't the child understand? 
9/8 when you simplified it.

If you divide two pizzas into 8ths, you have 8 in one pizza and 8 in the other pizza. 9/8 is all of the pieces in one plus one piece from the other.
You might draw a picture for the child showing the two pizzas.