There are lots of rules out there in the world, and we don’t always follow them. Most everyone I know has broken the speed limit at some point, and I hear some people are actually eating laundry detergent recently (ugh!). There are clearly marked speed limits on the side of every highway, and I trust there must be a label on the side of detergent boxes that says do not consume.

But breaking those rules isn’t necessarily going to ruin our day at work, unless we get caught. The rules that are used by Microsoft Excel to make formulas and functions, however, are inviolate. If you break them, you will get a wrong answer!

The ones I teach in my classes are lined out below. Let me know if you have any rules of your own that you think should be added to the list.

- Click your mouse in the cell where you want the answer to appear.
- Never refer to the cell that holds the formula inside the formula.
- All formulas and functions start with the equal sign.
- You must use the correct key press for mathematical formulas to work.
- It does not matter whether you use upper or lower-case letters to address a cell.
- Spelling counts! Be exact when typing formulas.
- Learn about Relative vs. Absolute Addressing, and be certain you are using the correct one.
- Make sure your formula is using the correct Orders of Operation.
- Whenever possible, use a cell reference for a constant, rather than a number.
- Never trust the computer. Always be certain the answer makes sense.