First I selected image 1 and started to work out the value of the triangle which I got as 6. Then I worked out the value of the square. I used trial and error until I got an answer of 8. I then checked my answers for the 1st image and got them all correct.
After that I opened up image 2. I had already knew what the triangle and the square were so I started to do the circle. I had done trial and error to work out the circle and got an answer of 4. i checked my answer which had included the triangle, circle and square and got them correct.
Then I started to work out image 5 which had the hexagons in it. I did my working out using the triangles, squares and circles and got an answer of 7.
Finally, i checked image 1,2,3,4,5 and 6 six to make sure all my answers were correct and they were. I answered the question mark because I had already known what all of the shapes were and got an answer of 21.
My Working Out for the question
Triangle+Pentagon+Circle+Circle =
6 + 7 + 4 + 4 =21