Change in position times mass times change in velocity. Now remember, mass times velocity is momentum. So this guy is change in momentum. In other words, this is the uncertainty of our position and this is the uncertainty of our momentum or velocity. And what this equation basically says is the following the less our change in axis, if this guy is very small, that means we know more information about our position, where our electron is located. And that means if this guy decreases and this is a constant, this guy must increase, the smaller our change in excess, the more we know about our position, the greater our change in b is, the less we know about our velocity.