Alternative Division, Multiplication, Addition, and Subtraction Algorithms Bundle 4+
Esa Helttula

 App Bundle $14.99

 Purchased Separately: $39.90
4 Apps in This Bundle
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Description
This bundle has 10 iDevBooks math apps. Save 62% compared to buying the apps separately.
Lattice Multiplication
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.
Grid Multiplication
The grid multiplication method is a twostep 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.
Egyptian Multiplication
Ancient Egyptians were able to multiply any two numbers by using just the ability to multiply by 2, and to add.
Russian Multiplication
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.
Column Division
The column division method is a simple variation of the traditional long division method. Lines are drawn to separate the digits of the divisor. Each placevalue column is solved from left to right.
Everyday ColumnAddition
The Everyday columnaddition 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 twodigit numbers. In the second stage the carries are done to obtain the result.
Partial Differences Subtraction
The partial differences subtraction method is a twostep process. In the example 936  580, each place value is first subtracted separately from left to right. The partial differences are added and 400  50 + 6 produces the answer 356.
Wired.com: “Esa Helttula’s apps are all fantastic for math learning and practice, and aren’t cluttered with minigames, incentives, or annoying music.”
TradeFirst Subtraction
The tradefirst 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, "tradefirst."
Equal Addition Subtraction
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.
The equal addition subtraction method is also called the ‘borrow and repay’ method 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 the 20th century.
LefttoRight Subtraction
The lefttoright subtraction method is a twostep 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 936500=436, 43680=356 and finally 3561=355.
Privacy
The apps have no ads or inapp 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.
Videos
Dozens of videos of these and other apps can be found at idevbooks.com.
Ratings and Reviews
Lefttoright or Righttoleft
Simple demonstrations of various math procedures: Lefttoright subtraction, Tradefirst subtraction, Equal addition subtraction, Partial differences, Column addition,
Russian multiplication, Lattice multiplication, Egyptian multiplication, Grid multiplication, Column division
In the settings you choose number of digits, animation speed, and other options.
Information
 Seller
 Esa Helttula
 Size
 6.7 MB
 Category
 Education
 Compatibility

Requires iOS 10.0 or later. Compatible with iPhone, iPad, and iPod touch.
 Languages

English
 Age Rating
 4+
 Copyright
 © Esa Helttula
 Price
 App Bundle $14.99
Supports

Family Sharing
Up to six family members can use this app with Family Sharing enabled.