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Trade-First Subtraction
This app can be used to teach and study the trade-first 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 subtraction problems with small and large numbers. The number of digits in the numbers can be set.
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 Trade-First Method
The trade-first subtraction method is similar to the traditional column subtraction method. The method has two stages. All of the "trading" or "borrowing" is done first. Then the subtractions are solved. This gives the method it's name, "trade-first."
In the Everyday Mathematics curriculum the trade-first method is the focus algorithm for subtraction.
The App is Easy to Use
The numbers are aligned automatically so that you can concentrate on solving the operations for each column.
Borrowing 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.
The App Has the Following Features:
- Each number can have from 2 to 5 digits
- Problems can be custom or random
- 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
- The lines separating the columns can be hidden
Video of the app
You can see a video of the Trade-First Subtraction app in action at my site idevbooks.com.
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 idevbooks.com 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.
What's new
Support for iPhone 5 and iOS 6.
Please visit idevbooks.com if you have feedback.
Screenshots
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- Last changed:
- Oct 15, 2012
- Category:
- Education
- Developer:
- Esa Helttula
- Version:
- 2.1
- Average Rating:
- 5.00 (1)
- Size:
- 1.6 MB
- Other Apps By This Developer
-
• Ancient Egyptian Multiplication
• Column Addition
• Column Division
• Column Subtraction
• Decimal Rounding
• Equal Addition Subtraction
• Everyday Column-Addition
• Fraction Math
• Grid Multiplication
• Lattice Multiplication
• Left-to-Right Subtraction
• Long Division
• Long Multiplication
• Partial Differences Subtraction
• Partial Products Multiplication
• Partial Quotients Division
• Partial Sums Addition
• Polynomial Addition and Subtraction
• Polynomial Long Division
• Polynomial Multiplication
• Russian Multiplication
• Visual Multiplication Table
• Whole Number Rounding
