10 printable sets · answer key on every set

Adding Fractions With Unlike Denominators Worksheets

CCSS 5.NF.A.1
20 problems per set
Answer key included

What this skill is

Adding fractions with different bottom numbers by first changing them to a common denominator.

When it comes up: Fifth grade.

The mistake to watch for

Adding the tops and the bottoms separately, so that 1/2 + 1/3 becomes 2/5. The pieces must be the same size before they can be added.

How to help

Find a number that both bottom numbers go into, such as 6 for 1/2 and 1/3, and rewrite both fractions with it.

Next: Multiplying fractions.

A worked example

1/2 + 1/3 = ___. A common denominator is 6. 1/2 = 3/6 and 1/3 = 2/6. Add: 3/6 + 2/6 = 5/6.

Words to know

fraction: A number that names equal parts of a whole, like 3/4.
numerator: The top number in a fraction. It tells how many parts we mean.
denominator: The bottom number in a fraction. It tells how many equal parts the whole is cut into.
equivalent: Equal in value. 1/2 and 2/4 are equivalent fractions.
simplify: To write a fraction with the smallest numbers that still name the same amount, like 6/12 = 1/2.

Practice

Add. Write the answer in simplest form.

Showing Set 1 · 20 problems

2/6 + 1/8 = ___
1/8 + 2/3 = ___
1/6 + 4/5 = ___
5/6 + 1/5 = ___
2/8 + 3/10 = ___
1/5 + 7/12 = ___
1/2 + 2/3 = ___
1/2 + 4/5 = ___
1/6 + 1/8 = ___
2/4 + 4/6 = ___
1/6 + 2/4 = ___
11/12 + 4/5 = ___
2/5 + 1/4 = ___
5/12 + 3/8 = ___
4/6 + 1/8 = ___
3/6 + 9/10 = ___
4/12 + 4/5 = ___
1/2 + 2/5 = ___
3/4 + 2/3 = ___
2/4 + 3/6 = ___

Download this set20 problems · answer key included PDF

Answer key

11/24
19/24
29/30
1 1/30
11/20
47/60
1 1/6
1 3/10
7/24
1 1/6
2/3
1 43/60
13/20
19/24
19/24
1 2/5
1 2/15
9/10
1 5/12
1

All 10 sets

Each set is a different list of 20 problems with its own answer key. Use the buttons above to look at one on this page, or download any of them as a PDF.

How these sheets were made

Problems are generated for each set and checked against 5.NF.A.1 before the sheet is built — no duplicates, and every problem falls inside the standard's number range.