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Same-Change Subtraction

Same-Change Subtraction
Download on the AppStore Click here to request a review of this app

  • App Store Info


This math app can be used to teach and study subtraction using the same-change rule. The app is easy to use and it has an intuitive interactive interface with customizable colors and other settings. The user can solve random subtraction problems.

Endorsed by teachers

Rita Zeni, Ecole Sandy Hill Elementary, Abbotsford, BC, Canada:

"The math apps by Esa Helttula allow students to practice and reinforce the specific computation strategies taught in class, with as much or as little scaffolding as necessary.
They also provide individualized feedback to each student, with an immediacy that is not always possible through pencil and paper practice. Being able to adjust the level of difficulty to suit their needs is also very motivating for the students. I am so glad to have come across this great educational tool!"

The Same-Change Rule in Subtraction

If you subtract or add the same number from both parts of a subtraction problem, the results remain the same. In this way a subtraction problem 667 – 289 is easier to solve as 678 – 300.

In the Same-Change Subtraction app the user can keep adding or subtracting the same number from both part of the subtraction until the subtraction problem can be solved easily.

In the Everyday Mathematics curriculum the same-change rule method is one of the algorithms for subtraction.

The App is Easy to Use

The numbers are aligned automatically so that the user can concentrate on solving the operations for each column.

The app has the following settings:

-The numbers can have 2 or 3 digits
-The current operation can be hidden
-Colors of the interface can be changed
-The speed of the animations can be set

Video of the app

You can see a video of the Same-Change Subtraction app in action at my site

Feedback and Requests for New Features

I have made this app to be a useful teaching and learning tool for those children and parents that use the Everyday Mathematics curriculum. New ideas to make this app better are welcome.

Please give feedback at iTunes or visit my site and give feedback there about this application. Please tell me if you have any ideas for new features.

My other math apps

Some of my 16 other math apps are Column Subtraction, Column Addition, Long Division, Long Multiplication, Fraction Math, Partial Differences Subtraction, Lattice Multiplication, etc.


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