Purpose of the toolTeaching the students the meaning of addition and subtraction (add and subtract).
Explanation of the toolOn the screen you'll see a bus.
Drag people to the bus.
Press 'Next stop'.
Drag people to the bus to add or drag people off the bus to subtract.
Press 'Show sum' and the sum appears.
If you press 'Next stop', you can continue to work on your sum.
Press 'Again' to make the bus start again (empty).