 Google says that the volume of a small grain of rice is 2 times 10 to the minus 8 meters cubed. But who wants to measure the volume of such a small thing using such a big unit? Let's convert this value into millimeters cubed. The thing to realize here is that when you have a unit with an exponent like this, it means the same thing as it does with a number. So if you have 2 cubed, it means 2 times 2 times 2. Here you have meters cubed. That means meters times meters times meters. Which makes sense if you think about it. These three meter units refer to the three dimensions of a cube, its length, its width and its height. So what we need to do here is to convert meters to millimeters three times over, one for each of those three meter units. So we just run through those conversions one after the other, like this. And we find that the volume of a small grain of rice is about 20 cubic millimeters.