How to pass variable as a parameter in Execute SQL Task SSIS?

In your Execute SQL Task, make sure SQLSourceType is set to Direct Input, then your SQL Statement is the name of the stored proc, with questionmarks for each paramter of the proc, like so:

Click the parameter mapping in the left column and add each paramter from your stored proc and map it to your SSIS variable:

Now when this task runs it will pass the SSIS variables to the stored proc.