How to make a customize resume formula?

[sdelavega]

I need to get the average of sales per account not per opportunity. So I’m trying to do an opportunity report and create a new customize resume formula.

I was thinking in something like this: ” Wonum / Account Name”,

but it doesn’t work.

What can I do to get the total sales import/number of accounts?

[Jakester]

How about creating a new custom field on the account object that's a roll-up summary of the sum of the opportunities? Then you can just make a report on the account object and leave the opportunity object out of it.

[sdelavega]

First of all, thank you for answer;  I am new with salesforce, could you explain me how to do it?

[Jakester]

Setup-->Customize-->Accounts-->Fields-->New

Roll-Up Summary-->Next

Name: Total Opportunity Amount-->Next

Summarized Object: Opportunities

Sum-->Amount

Next and Finish