How to calculate the average of a string of formula

[MrMM]

Hey,

I'm a teacher creating a dynamic mark book for my classes.

I've attached a forum template for you to have a look.

I need help with two formulas:

1) A formula to subtract Column B from Column C, and then work out the average of those answers for the whole column. The answer should be 1.4.
So, basically... C2-B2, C3-B3 etc... but then those answers need to have the average worked out for the column as a whole.

2) A formula to subtract Column B from Column C, and then work out the average of those answers JUST for the ones that have an X in column D. The answer should be 1.75

I hope this makes sense!!

Cheers,
Matthew

[Pepe Le Mokko]

Does this help ( providing no cells are empty in col B and C) ?

[MrMM]

That's brilliant, thanks so much, it works!!!