**– discover the exercise format interactively and experiment with it.**

The interactive math triangle (for iOS) is a virtual tool that can be used to illustrate and explore problems involving arithmetic triangles.

**Description of the app**

Calculation triangles encourage flexible thinking and calculation. With this calculation triangle you can solve tasks with calculation triangles - as offered in many exercise books and math textbooks - interactively by trying things out. This is how it works:

- Place tiles by touching the triangle with one or more fingers.
- Move tiles from one space to another by touching and dragging them.
- Delete a tile by dragging it out of the calculation triangle.
- Cover a field by closing the shutter.
- If you cross out a number, you can hide and show it again.
- Shake the math triangle to clear all tiles.

Arithmetic triangles are designed for the concept of productive practice. Arithmetic triangles can be used to work on problem-structured exercises, for example the following tasks:

- Find the missing numbers?
- Find out how many tiles are in the covered field?
- How do the marginal numbers change if…

… one (2, 3, …) tile is added/removed in each field?

… when one (two, three, …) tile is moved from one field to another.

… one (two, three, …) tile can be added/removed in two fields? - Can all three marginal numbers be odd?
- What is the relationship between the sum of the edge numbers and the number of tiles placed? Can you "create" any three edge numbers or are there restrictions?
- Invent your own tasks using the arithmetic triangle and give them to a learning partner.

**Browser and offline version**

There is also a Browser version, as well as offline versions for Mac and WindowsUnfortunately, they only work with a functioning Flash plugin.