Another numbers and this time is more complicated, so endless escape level 43 walkthrough will give you the right solution for the cheat answer
On the left side you can see two examples of triangles with number. Right now you have to determine the number in the middle.
The solution is really simple. We add together the top and bottom left and then subtract the lower right.
15 + 21 – 4 = 32
21 + 9 – 8 = 22
So you will have the answer number in the middle.
so for stage 43 :
37 + 24 – 6 = 55
change the number into 55 and pass this door with the key on the plant