Alternative Multiplication and Addition Algorithms Bundle
By Esa Helttula
This app is only available on the App Store for iOS devices.
This bundle has 7 iDevBooks multiplication and addition math apps. Save over 64% compared to buying the apps separately.
Vertically and Crosswise Multiplication
This math app is about a multiplication technique introduced by Shri Bharti Krishna Tirthaji in his book “Vedic Mathematics”, published in 1965. Tirthaji claimed to have found the mathematical content for his book in ancient sacred Hindu texts.
In the vertically and crosswise multiplication method the numbers are multiplied by altering vertical and crosswise multiplications so that two digit numbers can be multiplied in just three steps: vertical, crosswise, and vertical. Three digit multiplications require just five steps: vertical, crosswise, vertical, crosswise, and vertical.
Lattice multiplication is algorithmically equivalent to long multiplication. A lattice (a grid) guides the calculation. All the multiplications are done first and then the additions. The method was introduced to Europe in 1202 in Fibonacci's Liber Abaci.
In this groundbreaking book Fibonacci presented many algorithms for working with Arabic numerals. Ancient Indians and Chinese originally invented some of the algorithms. Fibonacci presented both the current standard long multiplication and also an originally Indian method called lattice multiplication, which is faster and more compact for working with larger numbers.
The grid multiplication method is a two-step process. In the example 39 x 24 the numbers are first broken up into 30 + 9 and 20 + 4, and written on a grid. Multiplying the row and column headers then solves each cell of the grid. Eventually the partial products 600, 180, 120, and 36 are added together.
Ancient Egyptians were able to multiply any two numbers by using just the ability to multiply by 2, and to add.
In this method is the the only multiplication facts we need to know are how to double and how to take half of a number.
The Everyday column-addition method was developed by a first grader. The method has two stages. In the first stage the digits are added one column at a time in each column. After the first stage some columns can have two-digit numbers. In the second stage the carries are done to obtain the result.
In the Opposite-Change Addition app the user can keep adding a number to one addend and subtract the same number from the other addend until the addition problem can be solved easily.
The opposite-change rules states that if you subtract a number from one addend and add the same number to the other addend, the sum remains the same. An addition problem 267 + 289 is easier to solve when it has been changed into 256 + 300.
The apps have no ads or in-app purchases and they do not transmit any data during the operation of the app. The apps also do not contain any links to other apps or the web.
Dozens of videos of these and other apps can be found at idevbooks.com.
7 Apps in This Bundle
- App Count: 7
- Category: Education
- Size: 14.0 MB
- Language: English
- Seller: Esa Helttula
- © Esa Helttula
Compatibility: Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.