What's New

- support for iOS 13
- new interface with support for latest iPad and iPhone models
- new theme colors

App Description

In the Opposite-Change Addition app the user can keep adding a number to one addend and subtract the same number from the other addend until the addition problem can be solved easily.

The opposite-change rules states that if you subtract a number from one addend and add the same number to the other addend, the sum remains the same. An addition problem 267 + 289 is easier to solve when it has been changed into 256 + 300.

Features:

- The numbers can have up to 3 digits
- You can set your own problems
- Three different themes
- Native interfaces for iPhone, and iPad

Other iDevBooks math apps

iDevBooks math apps have been reviewed and endorsed by Wired.com, Common Sense Media, and other respected sites and organizations.

Some of the over 40 other iDevBooks math apps are Visual Multiplication Table, Decimal Rounding, Whole Number Rounding, Column Subtraction, Column Addition, Long Division, Long Multiplication, Lattice Multiplication, Fraction Math, Partial Differences Subtraction, Partial Quotients Division, Partial Sums Addition, etc.

Feedback and requests for new features

New ideas to make this app better are welcome. Please visit idevbooks.com to give feedback.

Privacy

This app has no ads or in-app purchases and it does not transmit any data during the operation of the app. This app also does not contain any links to other apps or the web.

iPhone Screenshots

(click to enlarge)

Opposite-Change Addition screenshot 1 Opposite-Change Addition screenshot 2 Opposite-Change Addition screenshot 3 Opposite-Change Addition screenshot 4 Opposite-Change Addition screenshot 5

iPad Screenshots

(click to enlarge)

Opposite-Change Addition screenshot 6 Opposite-Change Addition screenshot 7 Opposite-Change Addition screenshot 8 Opposite-Change Addition screenshot 9 Opposite-Change Addition screenshot 10

App Changes

  • November 06, 2016 New version 4.0
  • November 06, 2016 Price increase: $1.99 -> $3.99
  • November 25, 2016 Price decrease: $3.99 -> FREE!
  • November 27, 2016 Price increase: FREE! -> $3.99
  • June 15, 2019 New version 5.2
  • October 22, 2019 New version 6.0