Adding and subtracting unlike fractions worksheets
Aligned with Common Core 5.NF.A.1
Printable fifth-grade fraction worksheets and how-to teaching pages: finding a common denominator, rewriting fractions, adding and subtracting fractions and mixed numbers with different bottom numbers, estimating to check answers, and word problems.
The worksheets
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How to Find a Common Denominator
1/4 and 1/6 rewritten as twelfths by listing multiples, a pair where one bottom number fits into the other, and the shortcut of multiplying the bottom numbers.
Find a Common Denominator
Pairs of fractions to rewrite with their smallest common denominator. Fewer has 6 pairs where one bottom number fits into the other, Standard has 8 pairs where both fractions change, and More has 10 harder pairs without the multiplier arrows. Includes an answer key.
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How to Add and Subtract Unlike Fractions
1/2 + 1/3 shown with fraction strips cut into sixths, 3/4 − 1/6 worked with twelfths, and a sum over 1 written as a mixed number.
Add Unlike Fractions
Fraction addition problems with different bottom numbers, each with spaces to rewrite the fractions before adding. Fewer has 6 problems with the common bottom number printed, Standard has 8, and More has 10 with some sums over 1. The answer key shows simplified answers too.
Subtract Unlike Fractions
Fraction subtraction problems with different bottom numbers, each with spaces to rewrite the fractions before subtracting. Fewer has 6 problems with the common bottom number printed, Standard has 8, and More has 10 with bottom numbers up to 36. The answer key shows simplified answers too.
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How to Add and Subtract Mixed Numbers
2 1/2 + 1 2/3 worked with sixths, trading 6/6 for a whole, and 3 1/4 − 1 2/3 worked with twelfths, trading a whole for 12/12.
Add and Subtract Mixed Numbers
Mixed number addition and subtraction with different bottom numbers and lines to work on. Fewer has 6 problems where one bottom number fits into the other, Standard has 8, and More has 10 where many need a trade. None of the Fewer or Standard problems need a trade. The answer key shows simplified answers too.
Is It Reasonable?
Fraction addition and subtraction problems with an answer given. Students round each fraction to 0, 1/2 or 1, estimate, and circle whether the answer makes sense. Wrong answers come from adding the tops and the bottoms. Fewer has 6, Standard has 8, and More has 10 with mixed numbers. Includes an answer key.
Unlike Fraction Word Problems
Word problems about recipes, ribbon, hiking, paint and gardens, with a work space for each. Fewer has 3 problems, Standard has 4, and More has 5 with mixed numbers. Includes an answer key.
Print the whole packet
One copy of every sheet above, in order. Tap + for more copies (up to 10).
For the parent or teacher
What it is
In 4th grade, students added and subtracted fractions with the same bottom number. Now the bottom numbers are different, like 1/2 + 1/3. The pieces are different sizes, so students first find a common denominator by listing multiples, rewrite each fraction with that bottom number, and then add or subtract the top numbers. Answers over 1 are written as mixed numbers. They also add and subtract mixed numbers, estimate with benchmark fractions like 0, 1/2 and 1 to check whether an answer makes sense, and solve word problems.
What comes next
Multiplying and dividing fractions.
How to teach it
- Teach in order or jump to whatever your student needs. A student may find common denominators easily and still be building the habit of rewriting both fractions before adding.
- Use fraction strips to show why 1/2 + 1/3 can't be added until both are cut into sixths.
- Have your student list multiples of each bottom number and circle the first one in both lists.
- Remind your student to multiply the top and the bottom by the same number.
- Ask "is the answer about the size you expected?" 1/2 + 1/3 should be a little less than 1.
Common mistakes
- Adding the top numbers and the bottom numbers, like 1/2 + 1/3 = 2/5.
- Changing the bottom number but forgetting to change the top number.
- Forgetting to trade a whole when the fraction being subtracted is bigger.
- Multiplying the bottom by one number and the top by another.
- Using a common denominator that isn't a multiple of both bottom numbers.