Need help creating a calculator

[gordonlu310]

You can start from here.

How to use the blocks to create a calculation

Hi all this is my first post i hope someone can help. Using the App Inventer how can i have a part of the app able to do the following calculation: (# x 50) / # the # are numbers the user can imput and when a button ''Calculate'' is hit it calculates the result and puts it on the screen. how would i use the blocks to do that? is it even posible? thanks any help would be much appreciated