Dactylonomy or finger-counting is normally discouraged in school. Which is unfortunate, because it is very interesting how different systems can be used to count up to different numbers. The classical system in Europe counts only up to five on one hand, by identifying the number of raised fingers with the abstract number. This can, however, drastically be improved.

For instance, using the binary system one can count up to 31 on one hand. Once the numbers 1, 2, 4, 8 and 16 are assigned to the fingers, as above, different numbers can be represented by raising or tucking in the fingers. If you want to count ever further, using the same principle on both hands further enhances the system up to 1023! Disadvantage: some dexterousness is required. The number 4 also constitutes some risk of misinterpretation&ldots;

My favorite system is less powerful but also very neat. Use your thumb to count on the three finger bones of each finger. This way, one hand can be used to count up to 12. The other hand is used to display the number of completed 12s, allowing for a total of 144.