I'm still not too sure what you asking for ,but I can tell you what I know
When it comes to uncertainties in one measurement ,for example you had to measure the length of a stick ,then you take the smallest reading in your tool ,for this case it's 0.1 when you use a meter rule ,so the smallest reading divided by the length of the stick

When it comes to lots of readings(let's say 3) ,like the time recorded for a specific action ,you find the mean of the 3readings then subtract from the original number ,square the answer you get and add it to the rest then divide by the number of readings given

This is what I mean
1) 10.4
2) 9.8
3) 11.0
My mean here is 10.4 so
1)10.4-10.4=0
2)9.8-10.4=-0.6
3)11.0-10.4=0.6
So after that ,I add the square of the answers
(0)^2+(-0.6)^2+(0.6)^2=0.72
Then divide by the number of readings
0.72/3 =0.24

There's a third type ,which is when it involves multiplications,addition ,subtraction and division of formulas ,like calculating the area or density,etc... ,and it's written in the form ( A (plus minus) B) ----(A+-B) then it's a different root to go but let me know if that's the one you need