How to Prevent Teen Number Reversals With One Easy Activity

I cringe when it happens- a student brings you a piece of work they are so proud of. They have figured out a tricky story problem or have used blocks to add two numbers together. Their thinking is exactly correct. But their answer? It’s written in reverse. Thirteen has turned to 31.

You want to praise the student for their work and their thinking, but that pesky teen number is sticking out like a sore thumb and you are stuck wrestling with whether or not you should say something *right now* even though it may crush their little spirit.

Don’t crush her spirit… help her understand!

I’m not being dramatic. I know you wrestle with the same. exact. problem. Your students can count teen numbers but what you need to do is to help them understand teen numbers. 

If this sounds like you, I have an easy-as-can-be teen number activity you need to try immediately! Grab a double ten frame, some fun counters, and a whiteboard and you are on your way to solving this problem once and for all!

THIS Activity Will Solve Your Problem!

Teen Number Ten Frame Activity
  1. Start by giving each student a double ten frame and ask each of your students to build a teen number such as 14 on the ten frame using counters.
  2. Ask your students how many counters they see on the top ten frame (10) and how many they see on the bottom ten frame (4).
  3. On the whiteboard, record what your students have built as a number bond. Do a think-aloud as you are writing telling your students “We had 10 in the top and 4 on the bottom and together that made the number 14”.
  4. Next, ask each of your students to record the same number bond on their own whiteboard.
  5. Ask your students to state an addition equation that matches the number bond you completed together. As you are writing the total, tell your students “I had 1 ten and 4 more ones” as you write. 

And That’s All I Need To Do?

The real secret to this activity is repetition. For some of your students, one time through this activity is enough. They will see the ten, they will see “some more ones” and they are good to go!
For other students, it will take many days. Many days before they truly notice each teen number has a group of ten and some more ones.

One More Tip

While the activity itself is important, the way students to transition from one problem to another is so important for you to notice! Consider these different approaches to building the number 18 after number 14 and what they tell you about the students.
  1. Student #1 clears the entire board and builds 18 by counting out individual counters starting at one.
  2. Student #2 keeps the top ten frame but clears the bottom and counts out 8 counters.
  3. Student #3 doesn’t clear their board at all and adds 4 counters to make the number 18.
  4. Student #4 clears the bottom ten frame but doesn’t appear to count as they place 8 new counters in the bottom ten frame- they “know” what 8 looks like in a ten frame.

I Love This… But What Will I Do Next?

This is a very concrete activity using individual counters. Your students still have room to grow! Moving forward try activities that:
  • Use a pre-grouped model of tens and ones.
  • Use a different representation than a double ten frame.
  • Move from concrete materials to a representative model
  • Move towards fluency with 10 + facts resulting in a teen number total.
AND, the next time your student comes to you beaming, ready to show you their math work, you won’t have to wrestle with yourself- you’ll be jumping for joy because they understand!

Related Resources:

Teen Number TPT Unit
This 5-Day Unit has EVERYTHING you need to lead a successful unit on understanding teen numbers to a small group of students. Assessment. Daily Lessons. Independent Activities. Tickets Out The Door. EVERYTHING

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