Visualize Aritmetic

Learn arithmetic by investigating a working calculator.

Fill boxes to Subtract

Seeing Is Believing

Check out these examples of MegaPro in action!


“MegaPro Calculator 5000 by Chris Ternoey is a powerhouse of mathematical understanding. Addition and subtraction with regrouping are two of the most difficult concepts to teach. This app has uncovered the secret!”

Katie Chirhart
Teachers With Apps

“Wonderful… An amazing tool for teachers to let young kids see what is happening as they add and subtract. It's so simple and really engages the children to understand what is happening with the place value system”

Lucy Ravitch
Teachers With Apps

“Great, fun app for kids… I enjoyed as much as my child did and it conveys the concept of addition and subtraction in a clear way! 5 Stars (out of 5)”

John Mklaine
App Store Review

“Amazing children's calculator… This calculator is great! I let all 4 of my children try it and they had a ton of fun. They especially liked the carry the one feature. I recommend it for everyone! 5 Stars (out of 5)”

Samie Pasteur
App Store Review