The idea of this exercise is that you realize the properties of the squares.
The first part is a set of instrucctions that guide you to go round the square and mark every corner oo it. Then you can count the corners (also named vertices) and verifiy that they are four.
This tells you that a property of the squares is that they have four corners or vertices.
The second part tells you go round the square and mark every side. In this way you can count the sides. The you verify that they are four sides.
This tells you that a property of the squares is that they have four sides.
