Adding onto Darth Maul`s solution:
After struggling with a solution to this puzzle. Here is hopefully an easier way for people to do this puzzle and not struggle as much as I did.
So here is a basic outline out what you will be looking at, but with different combination of numbers:
Left Column: Right Column:
003 - 009
007 - 008
006 - 007
004 - 008
20 32
*Note: This is just an example the numbers will be random everytime.
As you can see, if you add up all the numbers on the left side it equals out to the number 20. If you add up all the numbers on the right side, they equal up to 32. Now what you want to do is add both the totals together, so 20+32= 52. Now divide your overall total which is `52` and divide it by 2. So now your total is 26.
Now what you want to do is look at totals that you had by adding the numbers together from both the left and right side, which were 20 and 32 .. And find the prime number to make both the sides equal 26. So, on the left side (20) you always want to add .. In this case, the number would be 6, therefore 20+6=26. On the right side (32) you always want to subtract .. So, 32-6=26. Your prime number is therefore 6.
Now look at both your columns:
Left Column: Right Column:
003 - 009
007 - 008
006 - 007
004 - 008
And find which combination will equal out to 6. So, in this example you would choose 003 - 009. Do the simple math of 3-9=6.
I know by looking at this it`s going to be quite confusing at first, but you will get it in no time. You have to get the correct combination 3 different times before Carla is freed from the trap. I found the easiest way to get through all the math problems was having a calculator open on my computer. Sorry for the in depth solution, but I really wish I would have had something like this when I was trying to figure it out. Hope this helps anybody struggling with this puzzle. :)
Feel free to message me if you have any questions! :)