Multiplying and adding in the same spreadsheet

First of all, I've pretty much NEVER used Excel in my life. I've always been pretty daunted and intimidated by the tool.

What I want to do is simple. Basically I am doing a project that involves many, many tedious multiplication and addition problems. I have a bunch of values set for a certain attribute, and then a variable (this is the only thing I want to enter manually for each calculation) to multiply it with. After I find out the values of all the different attributes multiplied by the variables, I want to add all of the values together.


For example, say I have item A.

Item A has:
175 of the attribute with a value of 100 units. 175 * 100 = 17500
20 of the attribute with a value of 50 units. 20 * 50 = 1000
40 of the attribute with a value of 5 units. 40 * 5 = 200
17500 + 1000 + 200 = 18700 total units


It's a very simple operation, and I'd save a good 15-20 hours of tedious work by figuring out how to do this. Any help is greatly appreciated.

-Will-

To have a totals column and then total the column at the bottom
A B C
1 Attribute Units Total
2 175 100 17500
3 150 25 3750
4 225 75 16875
5 450 50 22500
6 0
7 0
8 0
9 Total 60625

If so the formula in C2 is =(a2*b2)
and he formula in C9 is =SUM(C2:C8)
Make sure you do not include C9 in the sum function or you will get a circular reference error.

This is what SUMPRODUCT was designed for......

Given Dunc's setup

=SUMPRODUCT(A2:A8,B2:B8)

This will multiply the columns and sum the results as required