Need help totaling account balances.

Recently my wife asked me to manage her accounting for her studio. I have chosen Excel 2007 rather than investing in some expensive accounting software. For most things, I can figure them out in Excel....but I am stumped on how to do the following correctly.

I setup a master worksheet bringing information from the rest of the worksheets in the workbook. In this worksheet I have given Column A as the account number, Column B is the student name, Column E is the balance due for that student, and Column F is supposed to be the account balance for all the students on that account number. The problem comes with the fact that I have a separate row for each student on an account, and I have no idea how to pull all student balances, lets say for account number 2, together.
I tried variations to VLOOKUP formula, but was only able to get one of the values for the account and not a sum of the values. Accounting is obviously not my strong suit, I use Excel for engineering not this. Can someone please help me?

Thank you very much...I never thought about that command. The sad part is that is exactly how I was sounding out the math for the formula.