So, next, I'm going to walk through an unplugged activity, where we learn about the concept behind variables, and that they are placeholders that hold values for us. So, I'm going to be walking through this. This is the unplugged activity from code.org. That's a little hard to see, so let me just show it to you on the screen. After the warm-up that we just walked through, then students would get this worksheet, and it asked them to think about a robot, and what is it supposed to do, and what does it look like? Then draw this robot on paper. When we're done, we're going to have three variables that we're going to keep track of information about our robot, its name, its number units tall, and its purpose. All right. So, I'm going to go and draw my robot. All right. So, this is what I drew. No, really I have zero artistic skill. So, yes, I found an image of a robot, I printed it out on paper, and I actually taped it on to my worksheet. So, then you can see I did do what I was asked to have done. So, figure out how many units tall this robot was. I was too lazy to go get a ruler, so I made up some units that seemed to be about the same height and I marked it off. It looks like my robot is four made-up units tall. I gave my robot a name, his name is Fluffy, and I gave him a purpose. Since he's all-smiley, I figured his purpose must be to make people feel happy. So, that was the first part. But then, I need to show that I'm going to have values for these variables: robot name, num units tall, purpose. So, got three envelopes, and I wrote the name or the placeholder name with a variable name on each of them: robot name, numUnitsTall, and purpose. Then, I got a piece of paper and I wrote down the value of the variable name for robot. That is, what is it that I want my robot to be called. Fluffy, and I folded up this paper up, and stuffed it in the envelope. Then, I did that again for the remaining two variables. "Four made-up units" was the value that it goes in the numUnitsTall variable, and "make people feel happy", was the value that goes into the purpose. So, then at the end, and here's the bottom of the worksheet, they're reminding us that we can use this variable name, robot name, and not necessarily have to know what's inside it. We can put different names, at different times inside that. That's a variable and that's what variables do. They're placeholder names that you can change the value that's inside there. So, what you can have your students do is, they could swap out the pieces of paper written in their robot names, envelopes, to switch them, so that I can get somebody else's robot name, or change the number of units tall, or change the purpose and whatnot. So, again, the idea that variables aren't static things, they're placeholders, and they hold values inside them that can change.