We estimate an answer in the range: `6` to `7`, because `2^6=64` and `2^7=128`, and `86` is between these 2 values.

`log_2\ 86 = (log\ 86)/(log\ 2)` `=1.934498451/0.301029995` `=6.426264755`

Our answer is between `6` and `7`, as expected.