# Question #7f91e

##### 1 Answer

Jan 18, 2018

#### Answer:

You add the percentage uncertainties.

#### Explanation:

If you are adding/subtracting variables you add the *absolute* uncertainties, if you are multiplying/dividing the variables you add the *percentage* uncertainties.

Finally, when raising a variable to a power you multiply the percentage uncertainty (and yes, that is also true for fractional powers e.g. square root you multiply by 0.5.)