PROBLEM:

Suppose that your bathroom scale reads your mass as 65 kg with a 3%  uncertainty. What is the uncertainty in your mass (in kilograms)?

SOLUTION:

The uncertainty is computed as 

\delta _m=\frac{3\:\%}{100\:\%}\times 65\:\text{kg}=1.95\:\text{kg} \ \qquad \ \color{DarkOrange} \left( \text{Answer} \right)

Therefore, the uncertainty in the given mass is 1.95 kg.