 So let's get this section started off by doing some simple arithmetic. We're going to do addition, subtraction, multiplication, division, and powers by arithmetic operators. Just plus, minus, multiply, divide, and take a power. Now if I click in this little cell here, you can see that it is a code cell. So I'm going to write code in there, but you can see I've got a bit of text there. As in Python with Julia we can write these comments, comment lines, starting them off with this pound sign. I can even put a space there. Anything after that pound sign for that line, Julia is going to ignore. It's not going to execute that code. So that's not marked down. That is just part of Julia itself. Same as with Python. All languages have their own little comment Key is there. This is Julia. We have the pound sign, the hashtag. It's just going to ignore that line of code. But let's get going. Two plus two. I'm putting these spaces in just for visual effect. You don't have to put them in there. To execute this line, the cell, I'm going to hold down shift and return, or shift and enter, or I can hit this little play button. Off we go, and we see this gets executed and two plus two indeed is four. Three minus four. What's that going to give us? Negative one. As simple as that. Multiplication, three times four, shift, enter, that's 12. Multiplication, as with most languages, is this little star sign, shift eight on most keyboards. Division is the fourth slash sign, so I can say 12 divided by four, and that's going to give me three. One thing I want you just to notice, see that was 12, but this is 3.0. There's a difference between those. This is an integer, this is a floating point value. We'll get to that in future. And just two to the power four. So in case you know Python, and Python, those will be double stars. But here in Julia, we have this carrot sign, shift eight, and I'm not putting in spaces there, although you could, just to remind myself visually that this is two to the power four, and indeed we're going to get 16. So simple arithmetic just using simple mathematical operators. Next up, we're going to look at the use of functions to do these simple calculations for us.