5th Grade · Number & Operations - Fractions
5.NF.A.1: Add and subtract fractions with different denominators, like 2/3 + 1/4
5.NF.A.1 is a 5th grade Common Core math standard in Number & Operations - Fractions. Here’s what it really covers, and how you can help your students learn it.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
The standard
Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd).
In plain words
Add and subtract fractions with different denominators, like 2/3 + 1/4.
Sample questions from student practice
These questions from Bobby's Math Club are the kinds of questions your students will see. You can try answering them to see what a student might see.
Question 1 of 3
Which common denominator could you use to add 3/4 and 5/6?
- 10
- 12
- 6
Where students can get stuck
- Adding the tops and the bottoms, so 1/2 + 1/3 becomes 2/5, which is less than 1/2.
- Changing the denominator but not the numerator, writing 2/3 as 2/12 instead of 8/12.
- Subtracting the smaller fraction from the larger in mixed numbers, so 3 1/4 − 1 1/2 becomes 2 1/4 instead of 1 3/4.
Effective teaching strategies
- Fold two same-size paper bars into thirds and fourths, then cut both into twelfths so students rename 2/3 as 8/12 and 1/4 as 3/12.
- Ask students whether 1/2 + 1/3 must be greater than 1/2 before they calculate, so they see why adding the tops and bottoms to get 2/5 cannot be right.
- Work 3 1/4 − 1 1/2 by renaming the fractions as fourths, and have students regroup 1 whole as 4/4 so the fractions can be subtracted.
Units that teach this standard
Find where 5.NF.A.1 lands in the program you teach. Each unit has a guide written for families. Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence.
Bridges in Mathematics
enVision Mathematics
Everyday Mathematics
i-Ready Classroom Mathematics
Illustrative Mathematics
Math Expressions
Don’t see your curriculum? Contact Bobby and we’ll see if we can help!
Share it with families
Families can read Adding and subtracting fractions like 2/3 + 1/4 for a plain-language look at this skill, with three questions to try together and ideas for helping at home.
Help every student practice fractions at home
In Bobby's Math Club, students practice at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free for every family.
See how it works for teachers
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.