Your page should contain a dataview that expects an object of a certain type. In this object you can have a (decimal) attribute that you can show on the page. Just drag and drop the attribute onto the dataview from the ‘connector’ tab in Studio Pro.
When you create or change the object you can set the value of your decimal.
It really helps a lot to follow some of the learning paths to get to know the basics quickly :)
you can show it using a custom string widget. i found this widget from the app store
This might help you