Kindergarten · Operations & Algebraic Thinking
K.OA.A.5: Fluently add and subtract within 5
K.OA.A.5 is a kindergarten Common Core math standard in Operations & Algebraic Thinking. 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
Fluently add and subtract within 5.
In plain words
Fluently add and subtract within 5.
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 6
There are 3 little birds on a branch. 2 more birds fly to the branch. How many birds are there now?
- 4
- 6
- 5
Where students can get stuck
Fluently add within 5.
- Counting every fact from 1 on their fingers, even 1 + 1, so the answers are correct but slow.
- Knowing 4 + 1 but not 1 + 4, treating them as two separate facts to learn.
- Saying 5 for 2 + 2, because 2 + 3 = 5 is the fact that comes to mind first.
Fluently subtract within 5.
- Mixing up a subtraction fact with its adding partner, saying 4 - 1 = 5 because 4 and 1 go with 5.
- Counting back and including the starting number, so 5 - 2 becomes "5, 4" and the answer comes out as 4.
- Saying the number taken away instead of the number left, so 5 - 4 is answered as 4 rather than 1.
Effective teaching strategies
- Practice a few facts within 5 in short, frequent rounds, such as 2 + 1, 3 + 1, and 2 + 2, until students answer without counting from 1.
- Show 1 + 4 and 4 + 1 with the same drawing and ask why they have the same total, so students learn that one fact covers two.
- Link facts such as 3 + 2 = 5 and 5 - 2 = 3, and have students check that a subtraction answer is smaller than the number they started with.
Units that teach this standard
Find where K.OA.A.5 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
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
Each skill has its own guide for families, with a plain-language look at the skill, three questions to try together, and ideas for helping at home.
Help every student practice problem solving 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.