deviation

[RolandVet]

Hi



I want excel to calculate the multiples of two cells... say A1 and A2
=A1*A2
Say A1 is 3 and A2 is 2... the calculated value is 6
That was the easy part.
Now my measure results were not exactly 3, they were say 3+-0.5. Now I want excel to take this deviation into consideration and give me the correct answer. This is supposed to be done by taking the two extreme values, calculating the answer, then averaging them and then also adding the std dev.

(2.5*2+2*3.5)/2=6
(3.5*2-2*2.5)/2=1
answer is 6 +- 1

Now i've tried to use +- and the mathematical equivalent from symbols but as soon as i add these symbols, excel does not register the data in the cell as a number, but as text thus leading to no calculation.

I know this can be done by using alot of extra cells and some complicated formulas but is there no easy way to do this?