Create an object that has a numeric value

Hey guys,
I’m new with Axure and I’m stuck on something I’m trying to do. I want to create a situation where there’s an object that has a numeric value. That’s mean, I want to create a situation that when you drag a block of gold and it reaches the old man, points will be added, and so the overall “money” value will vary depending on the type of lump.

A global variable is great for this purpose. You can also use the text value of any widget, visible or hidden.