This = That                    iOS  /  Windows  /  Macintosh



Build creative equations while practicing math facts


The desktop version of this app was originally called "Number String" (and legacy versions may be found below.) The name change is because the Macintosh and Windows desktop applications now match our terrific mobile app!


6 cards are dealt face up. Players use addition, subtraction, multiplication and division to make some or all of the first 5 cards equal the value of the sixth card. Parenthesis are available if needed. The scoring system encourages the use of as many number cards as possible. Multiplication and division operations earn additional points. After finding a solution, a "hidden" background picture is displayed.

The software behaves just like the card game it is based on in that it does NOT assure all problems have a solution. While the vast majority of problems can be solved, there may be occasions where the given cards cannot be combined to make the target value.

I encourage students in my class (8-10 year olds) to try and match the target number using all 5 cards. While this is not always possible it helps develop several number manipulation strategies. To further entice students along this line, a 200 point bonus is awarded for using all 5 cards and a visual record of the number of times this bonus has been achieved is recorded on the screen. (This makes it easy for me to look and see who has earned a sticker.)

And... IT'S FREE.

Screen Shots

iPod         iPod         iPad         iPad

App Store

Get  "This = That"  in the app store


Mac Download

Win Download

System requirements

MacOS 10.9 (Mavericks) or later

The earlier Macintosh version of Number String runs on PPC or Intel and requires MacOS 10.3 or greater. See below for download link.
The Legacy Macintosh version (1.0.6 is a FAT build for both PPC and 68k machines) works with systems 7.6 - 9.2, requires at least 6 MB of free application memory and 640 x 480 or greater screen resolution. See below for download link.

Windows requires Windows 7 or later.

The earlier Windows version of Number String requires Windows98 or better and 640 x 480 or greater screen resolution.

iOS 6.1 or later

For iPhone, iPod touch and iPad


version 1.2.4  August 2019

compiled for Mac and Windows as 64-bit  - code signed

version 1.2.3  December 2016 - Additional pictures including Claude Monet. Background pictures are now viewable without UI obstructions. Bug fixes.

Mobile version

version 1.2.2  September 2016 - support for iOS 10
version 1.2.1  February 2015 - 27 additional pictures. Improved support for iOS 8, iPhone 6 and iPhone 6 Plus.
version 1.2  February 2014 - added an option allowing the equal sign to appear on either side
version 1.1  October 2012 - support for iPhone5
version 1.0  August 2012

Desktop version for Macintosh and Windows

Version 1.2.3 (This=That) Desktop version now matches the mobile version.
version 1.5.3 (Number String) Added a preference for displaying an equal sign on the left. Corrected a cosmetic discrepancy. 10-2010
version 1.5 (Number String) New cosmetic skin. Added an optional timer. Added a scoring bonus for using all 5 cards. 10-2009
version 1.1 (Number String) Added a variety of number-card styles. 4-2009
version 1.0.6 (Number String) Solving a problem now results in manipulative objects being locked until a new problem is begun.
Last version for Classic Mac. (see Legacy Macintosh below) 4-2006
version 1.0.5 (Number String) Assorted bug fixes. 4-2005
version 1.0.4 (Number String) First public release: 3-2005.

Download the final version of Number String for Macintosh PPC / Intel

Download Legacy Macintosh 68k / PPC

Download the final version of Number String for Windows

Written with Livecode - Livecode