Need help with excel formulas newbie

I want to subtract C4 from B4 then add D4 to that total and have that total end up in E4. Please help

B4=15
C4=10
D4=4
E4 Should equal 9 but I cant combine formulas in the same cell or can I and how do I do this.

In cell E4, type/paste the following:


Cheers,