Because the second graph is equal to 1, it can be determined that this graph uses subtraction (it is easy to know that the two graphs are not in contact with addition and the two graphs are in contact with subtraction).

Figure 1: square+circle =3

Figure 2: Circle-Square = 1

Get: circle =2

Square = 1

Figure 3: Square+Triangle =6

Figure 4: Triangle-Square =4

Get triangle =5.

So the fifth figure = triangle+circle =5+2=7.