The very basics of shapes are to count the faces of each shape. Each shape has a different number of faces. Faces mean the sides of the shape. For this lesson, we will focus on 3D shapes. Let’s start with a square. A square has 4 faces. How?
Well, let's look at the sides of a square. There is an upper side, which is face 1. Which means that there is a lower side too, which is face 2, the third face is the front face. For the fourth face, you will have to use your imagination because you can’t see it drawn on the paper. If it has a front side, then it must also have a back side. So that’s it that’s how we know that a square has four faces.
Similarly, you can practice with other shapes such as triangle and rectangle. Keep it simple for better learning of the kid, since it is only math for 2nd grade.