If you can make one report the main report, and the other a sub report of this, you can pass the values around by using Shared variables.
In a formula in the main report, declare a variable thus (Basic syntax):
Shared MyVar as Number (or whatever)
and then set MyVar to the value you want to pass to the sub report. Then, in a formula in the sub report, declare the variable in exactly the same way (same name and data type) and the value will be passed.
Also, search in this forum on "Shared" - that's how I learnt to do this.
Bill.