How to make a buy system with points?

Im trying to make a buy menu where you spend points earned to get ammo. I have the points and ammo variables working and setup, however whenever i click the button to spend points to get ammo, either the numbers are all messed up, or nothing happens, this is my latest blueprint setup for the button is https://i.imgur.com/7ZMYm5W.png this currently does nothing but i am very confused and any help would be appreciated

I managed to fix it looking at other blueprints from tutorials, i fixed it by changing it to this if anyone’s wondering https://i.imgur.com/VXMpc46.png

You’re not really adding or deducting anything at the moment, you can’t just leave the nodes floating about. Try it like this: