The foldable half-meter, usually sold as keychain, is very easy to manipulate (for all ages, 4 years onwards).
It is a very portable measure instrument, which also allows the following use:
- For small children : make shapes (for example, all letters) and compare lengths (without numbers).
- For older children: more geometrical shapes (they can be deformed).
- For high-school pupils: plane geometry, trigonometry, algebra, combinatorics.
- For any age: creativity (shapes), anti-stress.
See the website of the project, by Andy Foyen.
