I am beginner and a novice for sums and math in general. I don't know the steps or techniques to understand how does the right hand side equals the left? Could someone clarify the techniques or steps taken? Or direct me to a resource that could?
$$\sum _{i=0}^{\lfloor \log_2 n \rfloor}\Bigl\lfloor \dfrac {n}{ 2^{i}} \Bigr\rfloor= 2n $$