App: Lattice Multiplication
Developer: Esa Helttula
Genres: Education

This app can be used to teach and study the ancient lattice multiplication method. Solving lattice multiplication problems is also excellent times tables practice. The app is very easy to use and it has an intuitive interface with customizable colors and other settings. The user can solve custom and random multiplication problems with small and large numbers.

Reviewed by Wired.com:

"This was one form of multiplication that I’d never done before, but the app taught me very clearly. It makes multiplying large numbers easier, and allows you to see it all visually"

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 Lattice Multiplication Method

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 Lattice Multiplication app

The Lattice Multiplication app allows the user to solve a lattice multiplication problem step by step and animates all the steps. In the steps the user will multiply or add. 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. 

Settings:

- The multiplicand can have up to 5 digits
- The multiplier can have up to 3 digits
- Custom and random problems
- The current operation for each step can be hidden
- The operands for the current operation can be highlighted
- There are 3 different themes: black, gray and gold
- The speed of the animations can be set

Other iDevBooks math apps 

iDevBooks math apps have been reviewed and endorsed by Wired.com, IEAR.org, Edudemic.com, Teachers with Apps, and other respected sites and organizations. 

Some of the other 40 iDevBooks math apps for iOS and Mac are Column Addition, Long Multiplication, Long Division, Column Subtraction, Visual Multiplication Table, Partial Differences Subtraction, Partial Quotients Division, Partial Sums Addition, Decimal Rounding, etc. 

Feedback and requests for new features 

New ideas to make this app better are welcome. Please visit idevbooks.com to give feedback. 

Privacy 

This app has no ads or in-app purchases and it does not transmit any data during the operation of the app. This app also does not contain any links to other apps or the web.

Release notes: