I would like your views on the use of the sum function. I always teach my students that the sum function should only be used to add up a range of cells and it should not be used for any other calculation. I have just given my classes a little test and I have seen various uses of the sum function. I don't know if they have been taught these ideas by another teacher, or if they have come from home, or possibly just trial and error! Some students seem to include almost every calculation in the sum function. They always get the correct answer so they find it hard to accept me telling them that they are wrong. Here are some examples: sum(A2 + B2 + C2), Sum(B2*C2), sum(A2+B2*C2), sum(A2,(B2*C2)) I am tending to want to give a higher mark to those who use the sum function correctly. Am I just being pedantic? Does it, in fact, matter? I am beginning to doubt myself!!!