Is 3, because the square in the figure 1 represents 1 and the circle represents 2. There is a circle in the square that represents the operation 1+2=3, and square+circle =3.

There is a square in the circle in Figure 2, which represents the operation 2- 1= 1.

The triangle in Figure 3 represents 5. There is a triangle in the square representing the operation 1+5=6.

There is a square in the triangle in fig. 4 representing operation 5- 1=4.

In Figure 5, a circle in the triangle represents operation 5-2=3.

It should be like this.