Formulas in Excel 2007
 
Combining the Arithmetic Operators
 
The basic operators you've just known can be combined to make more complex calculations. For example, you can add two cells together, and multiply by a third one. Like this:
  
= A1 + A2 * A3
Or this:
= A1 + A2 - A3
And even this:
=SUM(A1:A9) * B1
 
In the above formula, we're asking Excel 2007 to add up the numbers in the cells A1 to A9, and then multiply the answer by B1. You'll get some practice with combining the operators shortly. But there's something you need to be aware of called Operator Precedence.
 
Operator Precedence
 
Some of the operators you have just met are calculated before others. This is known as Operator Precedence. As an example, try this:
 
. Open a new Excel 2007 spreadsheet
. In cell A1 enter 25
. In cell A2 enter 50
. In cell A3 enter 2
 
Now click in cell A5 and enter the following formula:
 
=(A1 + A2) * A3
 
Hit the enter key on your keyboard, and you'll see an answer of 150.
 
The thing to pay attention to here is the brackets. When you place brackets around cell references, you section these cells off. Excel 2007 will then work out the answer to your formula inside of the brackets, A1 + A2 in our formula. Once it has the answer to whatever is inside of your round brackets, it will move on and calculate the rest of your formula. For us, this was multiply by 3. So Excel is doing this:
 
. Add up the A1 and A2 in between the round brackets
. Multiply that answer by A3
 
Now try this:
 
. Click inside A5 where your formula is
. Now click into the formula bar at the top
. Delete the two round brackets
. Hit the enter key on your keyboard
 
What answer did you get? The images below show the answers with brackets and without: