# Equal Addition Subtraction

### for iPad and iPhone

This math app can be used to teach and study the equal addition subtraction method. 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 equal addition subtraction method

The equal addition subtraction method is also called the borrow and repay method, European subtraction, or equal additions method for subtraction. Today the method is used in Australia and Latin America. The equal addition used to be a very popular method for subtraction in US until the middle of 20th century.

The method is based upon the idea that adding the same amount to two numbers will not affect the difference between the two numbers. The process can be thought as:

- Work column by column from right to left

- When the digit of the first number is smaller than the corresponding digit of the second number, add ten to the digit of the first number and one to the digit of the second number in the next column to the left.

## Easy to use

The numbers are aligned automatically so that you can concentrate on solving the operations for each column. After you solve the operation for each column the correct answer will fly to the right place. If the user taps the wrong button the answer will appear above the keyboard but it will not move.

## Features and settings:

-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

-Different interface on iPhone and iPad

-Works in portrait and landscape orientation on the iPad

## Equal Addition Subtraction Videos

## Equal addition subtraction with three digit numbers

705 - 257

## Equal addition subtraction with five digit numbers

76001 - 75733

## Equal Addition Subtraction in the Apple VPP Store for Education

The Volume Purchase Program allows participating educational institutions to purchase iDevBooks math apps in volume and distribute them to students. All iDevBooks math apps offer special 50% discount for purchases of 20 apps or more for participating educational institutions.