Excel how to add a multiple "name" cell with is calculation to a cell on a separate page

[tamhav]

Ok hi guys,

Ive only opened my eyes to the potential of excel recently, but now im stuck on a formula (please note i dont know correct terms to use - sorry if it gets confusing like that)

ok i have a drop down boxs, lets call the names in them product 1, product 2, product 3 etc (in cells E18 - E28)... if u chose a product it automatically spits out a formula in cell G (so G18-G28 all the same formula)

now i need on a seperate sheet, to calculate how many times "product 1" (E cells) + its formula (in G cells) total too.

sheez im sure i make it sound allot more complicated that it is but i need help

thanks guys/girls