App Shopper: Column Subtraction (Education)

App Activity

Dec 02 '11	Version 2.0
Aug 26 '11	$1.99 -> $3.99
Aug 12 '11	$3.99 -> $1.99
Aug 03 '11	Version 1.5
Jun 13 '11	Free -> $3.99
Jun 12 '11	$3.99 -> Free
Sep 01 '10	$1.99 -> $3.99
Aug 18 '10	Version 1.4
May 23 '10	$.99 -> $1.99
Mar 05 '10	Version 1.3
Jan 07 '10	Version 1.2
Dec 09 '09	New App: $.99, v1.0

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Column Subtraction

iOS Universal

This math app can be used to teach and study the column subtraction method. The app is easy to use and it has an intuitive interactive interface with customizable colors and other settings. The user can solve random or custom subtraction problems with small and large numbers. The number of digits in the numbers can be set.

The column subtraction method is also known as columnar subtraction, long subtraction or longhand subtraction.

Review by professor Tim Pelton

Tim Pelton, assistant professor of Mathematics Education at the University of Victoria:

“If your goal is to help your child to master the traditional subtraction algorithm then Column Subtraction may be the ideal App.”

“With the ‘show current operation’ option turned on, they are constantly reminded of the next step, which can lead to efficient practice of the procedure. Then by turning off the current operation your child is able to practice remembering the steps on his/her own. Because no wrong entries are allowed the app provides a passive form of positive reinforcement and your child will likely improve in both confidence and competence with respect to the procedure.”

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!"

Easy to Use

The numbers are aligned automatically so that you can concentrate on solving the operations for each column. Pressing the borrow-button carries out borrowing which is animated step by step so you can see what happens. Borrowing over several columns is also supported.

After you solve the operation for each column the correct answer will fly to the right place. If the user presses the wrong button the answer will appear above the keyboard but it will not move.

25 Six-piece Jigsaw Puzzles

The puzzles are pictures of cute animals. Every time the user solves one addition problem, he will see one more piece of a six-piece picture puzzle.

To see all 25 complete puzzles the user has to solve about 200 column subtraction problems (Some pictures may appear twice before all different pictures have been shown).

The picture puzzle feature can be turned off and on at any time.

The App has the Following Features and Settings:

-The number of numbers to subtract can be 2 or 3
-Each number can have from 1 to 5 digits
-Problems can be random or custom
-The current operation for each column can be hidden
-The operands of the current operation can be highlighted
-Colors of the interface can be changed
-The speed of the animations can be set
-25 6-piece jigsaw puzzles of animals are shown one piece at a time
-The jigsaw puzzles can be hidden
-Different interface on iPhone and iPad
-Works in portrait and landscape orientation on the iPad

Video of the app

You can see a video of the Column Subtraction app in action at my site idevbooks.com.

My other iDevBooks math apps

Some of my 15 other math apps are Column Addition, Long Division, Long Multiplication, Lattice Multiplication, Multiplication Table, 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 give feedback at iTunes or visit idevbooks.com and give feedback there.

What's new

- The app is now universal and it has custom interfaces for iPhone and iPad
- On the iPad the app can be used in portrait or landscape orientation
- Some minor bugs on iPhone / iPod Touch have been fixed
- Retina resolution graphics for iPhone 4, iPhone 4s, and iPod Touch 4G/5G have been added
- Please give feedback and get information about 18 other math apps by visiting http://idevbooks.com