SOLVED// How do I create sums for variables?

I have this mini .capx example of objects placed on screen when buttons are pressed. Each object has a number variable which will be added to the value of another previously added object's variable. Each time I press the specific button, number is added, but when I add the second object, value of first object is replaced with the second object's value. How do I make them to sum when selected, and not replace each other?

drive.google.com/file/d/0B09lLdP7JoIAZ1hHYjFlRms4OXc/view?usp=sharing

Not sure if I understand correctly, but there's the action add to variable..

I know about the native expressions:

+ (addition)

• (subtraction)

* (multiplication)

/ (division)

But how do I make only the selected objects to be summed(added)? Those which are already placed on screen only. ANd also, if one object will be removed, I need to know how to subtract it's value from the total sum.

If I write Blue. point+Red. point+Green. points, they all add at once. But I want them to be added only when placed on screen. What would be the right command?

I think you mean something like this:

On object2 created - object1 add to variable value = object2.value

On object2 destroyed - object1 subtract from variable value = object2.value

With multiple objects it would probably be easiest to use the family feature and have the adding event be in a function.

Maybe using the is on screen - condition, would be an option.

I've made it! Thank you for your suggestions!