Let's talk a little bit about setting up formulas in a Microsoft Excel Worksheet.  We will start by setting up a simple Order worksheet.  Starting in position "A1" by typing in the word "item".  Continue to the next position "B1" and type in the word "quantity".  Fill position "C1" with "EXT", position "D1" with "Tax", and position "E1" with "Total".  The data contained in the 1st row are your headers.

Now that you have your header information go to the next position "A2- A3".  Type in an amount (i.e. $12.00).  Under the header "Quantity" type in a number (i.e. 2).

Under the "EXT" header we will create an Excel formula.  Starting with the equal sign "=" type "A2*B2" (i.e. =A2*B2).  

Using the data from above A2*B2 is the same as 12.00 x 2.  In the "EXT" column position "C2" it should read 24.  You have just complete an Excel formula.

= (equal refers to the sum)

+ (the plus is for addition)

- (the minus is for subtraction)

* (the asterisk is for multiplication)

/ (the forward slash is for division)