Well, let me give you a clue. So if we have plus, actually let me change this, minus f of x plus h, g of x. I can't just subtract, if I subtract it, I've got to add it too, so I don't change the value of this expression. So plus f of x plus h, g of x. Now I haven't changed the value, I just added and subtracted the same thing. But now this thing can be manipulated in interesting algebraic ways to get us to what we all love about the product rule. And at any point you get inspired, I encourage you to pause this video. Well, to keep going, let's just keep exploring this expression.