Calculating errors.
if uncertainty in x = 5% and $y=\frac{1}{100} x$ and $z=x+y$ calculate the error in $z$ when the uncertainty in y is 1%, 5%, 10%

Not sure if the error in y is the product of $\frac{1}{100}$ of the uncertainty of x and the uncertainty of y... or is it the addition of the two?

If it's the product then the error propagation when calculating the error in z is just 5% regardless of the three uncertainties in y.

Is it right to conclude that when one value is much larger than the other the error of the smaller value is almost neglected?

Question

Calculating errors.
if uncertainty in x = 5% and $y=\frac{1}{100} x$ and $z=x+y$ calculate the error in $z$ when the uncertainty in y is 1%, 5%, 10%

Not sure if the error in y is the product of $\frac{1}{100}$ of the uncertainty of x and the uncertainty of y... or is it the addition of the two?

If it's the product then the error propagation when calculating the error in z is just 5% regardless of the three uncertainties in y.

Is it right to conclude that when one value is much larger than the other the error of the smaller value is almost neglected?