Keywords - Subtraction, the four operations.
Purpose - Understanding the mechanics of subtraction.
Pre-requisites - Knowing how to count in the local language.
Didactic materials - Music.
Description - The space is divided between the stage and the audience. The trainer subdivides the group into subgroups according to the operations to be demonstrated.
To describe the exercise we will take the example of “6-4”.
In subtraction the 6 represents the minuend and the 4 is the subtrahend.
The trainer creates a subgroup made up of 10 elements. The minuend is represented by 6 components. The subtrahend consists of the remaining 4 people.
The group that represents the minuend builds a static scene by simply going onto the stage with all the participants remaining immobile and making contact with each other.
Once the static scene is put together the trainer starts some music. With the music the first component of the subtrahend enters the scene with an amusing walk and moves toward the minuend static scene touching one component of the minuend with a hand. The person selected has to imitate the walk following the person who chose them in a sort of procession and then head off the stage. The same will happen with the other three members of the subtrahend; each one entering with a unique walk that is different than the previous one.
At the end of the sequence, the difference remains on the stage which, in this case, is 2.
Duration - About 30 minutes.
Variations - An interesting variant to try at another moment could be doing an operation where the minuend is smaller than the subtrahend to demonstrate that it is not possible to carry out with absolute numbers or to illustrate the need for relative numbers.
Observations - This activity works well if the group is comfortable with physical contact and the participants have already overcome the embarrassment of exhibiting themselves in front of their classmates.