Counting on and back to add and subtract
In 1st grade, children learn that adding 2 means counting on two more and that subtracting 2 means counting back two.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 1st grade practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
What number do you get if you start at 4 and count on 2?
- 6
- 5
- 7
Why this matters
Starting at 7 and counting on, instead of counting every object from 1, is a big moment in how your child thinks about numbers. It is the bridge to faster strategies like making ten and using known facts, which carry your child through adding bigger numbers in 2nd grade. Without it, children often keep counting from 1, which gets slow and error-prone as numbers grow.
Where kids can get stuck
- Starting over at 1 every time, counting out all 7 blocks and then 2 more to solve 7 + 2.
- Counting the starting number as the first step, saying "7, 8" for 7 + 2 and answering 8 instead of 9.
- Losing track of how many steps have been counted on past 3 or 4, then stopping too early or going too far.
How you can help
- Walk up the stairs together, starting on step 5. Ask, "If we go up 3 more, which step will we be on?" Count each step aloud: 6, 7, 8.
- Hide 6 toys under a towel, tell your child how many are hidden, then add 2 more on top and ask how many there are now, without lifting the towel.
- Play a board game with dice and encourage your child to count on from the space they are on rather than counting from the start of the board.
Want a little more? Watch the kid-friendly video below together, or try Bobby's Math Club for free practice that adapts to your child.
Kid-friendly explanation
Questions parents ask
Why is my child learning to count on instead of counting everything?
Counting on is quicker and shows that your child understands a number as a whole amount. Knowing that 7 already means seven things lets them start there and add the rest. It is an important step between counting every object and knowing facts from memory, and it builds confidence with bigger numbers.
My child keeps getting answers that are off by one. Why?
This usually happens because your child says the starting number as the first count. For 5 + 3, they say "5, 6, 7" and answer 7 instead of 8. Try holding up a finger for each number counted after 5, saying "6, 7, 8" while raising three fingers. Seeing three fingers helps them notice that the starting number is not counted again.
When should my child stop counting on and know facts?
Counting on is a stepping stone, not the end goal. During 1st grade, children are expected to become fluent with sums within 10 and to use strategies for sums to 20. By the end of 2nd grade, they are expected to know all sums of two one-digit numbers from memory. Counting on gradually gives way to faster strategies.
Make learning math fun
Bobby's Math Club turns 1st grade math practice into something fun to do together.
- Unlimited free practice
- A few minutes a day, at just the right level
- Hints when they are stuck, and a celebration when it clicks
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.
Ready to watch your child’s confidence grow?
Your 1st grade child can start today with free, unlimited practice that grows with them.
Join the clubNote for teachers: This skill is covered by Common Core math standard 1.OA.C.5: “Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).” Learn how Bobby's Math Club can help your students grow. (Common Core 1.OA.5)