In many of the cells where I have formulas entered, I have validated them to allow only whole numbers less than zero to prevent users from accidentally changing or deleting the formulas. This seems to work fine until someone hits delete, which allows the user to erase the formula and get away with it. I cannot use protection because then I can't merge cells, so I'm wondering if it's possible to use something else in the Validation field which won't allow anyone to change or delete the formula I worked so hard to come up with.