This game allows to classify and compare the main units of length. The smallest units are placed on the left, the largest on the right.
The gray label can be moved over two units. It indicates the relationship (the multiple) between the two chosen units of length:
Once all the units have been classified, the game continues with labels representing objects whose order of magnitude is characteristic of a unit of length. Each label must be placed under its characteristic units. Thus the Burj Khalifa tower located in Dubai is close to the km with its 828 m height.