 The equation we're going to use is so that equals the mass of solute, mass of solution. So for these ones, I kind of take this, because this is just one variable, but it looks like a bunch of stuff. What I do is just take this and make it like an x or something, so it'll be easier on them. So let's just make this equal to x. So we can kind of cross this part out, so we're looking for x. OK, so the mass of solute, well that's what we're looking for, percent weight, weight. Well, we don't really have to do that x thing on this one, zero zero percent. And the mass of solution we know too, this one here. So we've got to get rid of all of this other stuff on this side of the equation. Or we could just plug in numbers and then move it around if we want to do that. It's the same thing. But let's just do it this way, where we take everything and remove it from the one side of the equation. So, we close that. So, this is multiplied by 100, so let's divide both sides by 100 percent. OK, so we take this, so we can take this. So that's what that actually looks like. So let's divide both sides by 100 percent and get that out of there. This equation, mass of solute over mass of solution equals x times 100 percent, or divided by 100 percent. But we want to get this mass of solution out of there, so we'll multiply it by that, which gives us what we're looking for. So, the new equation is the mass of the solute, which is what we're looking for, equals the mass of solution times x divided by 100 percent. So, the mass of the solution, 2.50 times 10 square grams, multiplied by 0.900 percent divided by 100 percent. Like that. Percent, remember, is just the union, so we can cancel that out. OK? So percent over percent cancels out. So that just gives us, leaves us with grams. So all we got to do here is just multiply these numbers together. 2.5 square times 0.9 divided by 100. And I got 2.25 grams of solute.