So negative 16 times one minus 0.1t. And if we want, we could distribute the 16 or we could just leave it like this. But we're ready now to answer our questions. We could write this as the rate of change of the number of words we know with respect to time. Or we could use the alternate notation. We could say this is w prime of t. Either way, it's going to be equal to this thing. It's negative, let me do that same color.