# Left-to-Right Subtraction - Educational Math App for iPhone & iPod touch

July 21, 2010 in Education (F)

[prMac.com] Espoo, Finland - Independent developer Esa Helttula is pleased to announce the release of Left-to-Right Subtraction 1.0, a new educational math app for iPhone and iPod touch. The app can be used to teach and study the left-to-right subtraction method.

The Left-to-Right Subtraction Method:
The left-to-right subtraction method is a two-step process. In the example 936 - 581, the number to be subtracted is first written in an expanded form: 500 80 1. Each of the parts is then subtracted from the starting number. In our example 936-500=436, 436-80=356 and finally 356-1=355. In the Everyday Mathematics curriculum the left-to-right subtraction method is one of the algorithms for subtraction.

Each step of the multi-step process is animated and the numbers are aligned automatically so that the user can concentrate on solving the operations for each step. After you solve each sub-operation the correct answer will fly to the right place. If you press the wrong button the answer will appear above the keyboard but it will not move.

The Interface Supports Learning:
If the user presses the wrong button the answer will appear above the keyboard but it will not move. "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", said assistant professor of mathematics education Tim Pelton in his review of Column Subtraction, a sister app of Left-to-Right Subtraction that uses the same kind of input method.

Difficulty can be set with Settings:
* The numbers can have 2 or 3 digits.
* The current operation 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.

The Everyday Mathematics Curriculum:
Everyday Mathematics is a new mathematics curriculum developed by the University of Chicago School Mathematics Project. In the United States over 3 million students in 185,000 classrooms are currently using Everyday Mathematics. Parents may find it hard to help their children with the "new math" and apps like the Left-to-Right Subtraction can help both children and parents.

Device Requirements:
* iPhone and iPod touch
* Requires iPhone OS 3.0 or later
* 0.4 MB

Pricing and Availability:
Left-to-Right Subtraction 1.0 is only \$1.99 USD (or equivalent amount in other currencies) and available worldwide exclusively through the App Store in the Education category. This is a new app in a series of 10 popular educational Everyday math apps for iPhone. Esa Helttula's traditional mathematics apps include Fraction Math, Long Division, Long Multiplication, Column Addition and Column Subtraction.

Esa Helttula is an independent developer in Espoo, Finland. He has been an algorithm visualization researcher at the university of Tampere. Currently he is interested in making mathematics more fun and easy with the use of technology and develops critically acclaimed educational math apps for iPhone and iPod touch. Copyright (C) 2010 Esa Helttula. All Rights Reserved. Apple, the Apple logo, iPhone and iPod are registered trademarks of Apple Inc. in the U.S. and/or other countries.

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