If the volume of each small cube is $3$ cm${}^3$, what will be the volume (in cm${}^3$) of the following shape?

On a closer look, we see that the given shape is composed of $10$ individual units of the small cubes like this:





Volume of the individual small cube $=3$ cm${}^3$
Therefore, volume of the shape $=$ (Number of small cube) $\times$ (volume of individual small cubes) $=10\times 3=30$ cm${}^3$