Number line with numbers 1 - 7

Accessible Number Line App: University AT project

This app addresses the issue of teaching number line concepts in a digital format.


Number lines are a foundation math skill; number lines help students visualize number sequences and demonstrate strategies for counting, comparing, adding, subtracting, multiplying, positive and negative numbers, fractions and so much more! As our classrooms embrace technology, how will students with visual impairments use digital number lines to learn these concepts? Currently, number lines are not accessible with a screen reader.


A computer science student team at the University of North Carolina approached the issue of how to make a digital number line activities accessible on an iPad running VoiceOver. During the spring 2019 semester, this team looked at typical number line activities and fleshed out various digital activities to teach these skills in small steps. We talked with several TVIs who are currently introducing  number line concepts with young students using tactile number lines. (Stay tuned for a related post about teaching number line skills using tactile number lines!) The computer science team learned about VoiceOver and researched how to code the app correctly to incorporate standard accessibility features that are often lacking in mainstream educational apps. (Example: How to integrate accessible drag-and-drop commands) Once the computer science students understood the basics of teaching a blind child how to use a tactile number line and accessibility features, work began on an accessible number line concept app.

Beta Version of the Accessible Number Line App

At the end of the semester, the computer science team produced a working accessible number line and an activity that included asking the student with visual impairments to move the astronaut to the desired place on the number line. Keeping the number line similar to visual/tactile number lines, the digital number line has visual tick marks (that make a “tick” sound as a finger is dragged down the digital number line) and numbers are placed below the number line. It is important that when dragging a finger down the number line that the numbers are not announced – only the tick mark is heard. Students can hear a tick mark and count the ticks and then choose to drag a finger down to hear the actual number. This is the same method that blind students use when working with a tactile number line. If the numbers were announced instead of the tick marks, it becomes very confusing when students are using the number line to add. (Example: When adding 2 + 3, the student counts the tick marks (one and two) stopping on the second tick mark; if desired, the student can confirm he is on two by dragging his finger down to the number 2. Then, from the second tick mark on the number line, the student then counts three more tick marks, arriving on the 5th tick mark. If the number line announced each number at the tick mark, when the student moved to the third tick mark and the student counts ‘one’, VoiceOver would announce ‘three’.  Very confusing! 

The video below demonstrates the second level game on the beta version of the Accessible Number Line app.

Next Levels 

Similar to other semester long university projects, this app has not been completed and is currently used as a proof of concept. Hopefully, another computer science team will continue on this app in the fall. This beta version is also being used as a proof of concept app to spark discussions with other app developers. The first level of the app (which has not been built out yet) should include an interactive tutorial where the student learns about the number line, how to follow the number line, counting the tick marks, finding the numbers below the line, and learning about the range of the numbers on the number line. The next sequential step would be to find the astronaut on the number line and identify his position on the line.

Other games might include two items on the number line (astronaut and rocket ship) and determining which number is bigger or comparing the numbers (greater than, less than or equal) by selecting the appropriate symbol. Activities might include adding two numbers. Another series of games might include having different ranges of numbers (the current number line is 0 – 5). A number line might be created that counts by twos, fives or tens. Activities with negative numbers and positive numbers, fractions, etc. are additional game ideas. An often challenging number line activity is finding what is half way between two given numbers.

A big thanks to the student team, grad student mentor, and professor in the Serious Games course and the computer science department at the University of North Carolina for supporting accessibility-related projects!

Your Input Please!

What skills are you (or mainstream math teachers) teaching your students using number lines? Do you have additional ideas on activities that can be added to the Accessible Number Line game? Do you have cool tricks or tools that you are using to teach tactile number line skills? Please share your experiences in the comment section below!

Do you have a game activity idea that would teach a specific educational concept? Let us know! Or better, yet, contact the computer science department at your local university!

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