Sort these into SI base quantities and derived quantities: length, density, mass, power, time…

Step 1. Base. Length, mass, time, amount of substance and temperature.

Step 2. Derived. Density is mass over volume ($\text{kg m}^{-3}$). Power is energy per time ($\text{kg m}^2\,\text{s}^{-3}$). Electric charge is current times time ($\text{A s}$).