What Are Logarithms? (The inverse)

A logarithm is the inverse of exponentiation. If $2^3 = 8$, then $\log_2(8) = 3$. The logarithm asks: "What power do I raise the base to get this number?"

Think of it like this: exponentiation builds up ($2 \times 2 \times 2 = 8$), and logarithms break down (how many times did you multiply $2$ to get $8$?).

You'll use this inverse relationship constantly. When algorithms repeatedly divide by $2$, that's where $\log_2$ comes from.