What happens if the number of values in the rows or cols attribute doesn’t add up to 100 percent?

The browser makes them add up. I think it varies how. But typically, the browser makes i proportional to the entered values, if possible.

Say, if in a 5 column table each column has the width 10%, the columns will be of equal width. If 4 is 10% and one is 20%, the 20 one will be twice the width of the others and so on. If one column lacks a width it will take up he slack, i.e. it will be about the width that's lacking to make it add up, provided TABLE doesn't have a width that prevents this. This is in my experience, there may be browsers that doesn't do it like this.