Hi. Within this lecture, we're going to give you your first assignment. So, you're going to be building the worst calculator ever. I'm calling it worst because this is so simple, we can only do four basic operations in this calculator. Let me give you an example. So, I write 10 and 20, I can sum them, and I can subtract one from each other. I can just try to multiply them or divide one by another. So, as you can see, this works. Of course, this is not an app that you may want to upload to App Store but this will give you a good chance to practice what you have been learning so far. 

So, maybe you're thinking right now, there are some elements in here that we haven't covered yet. Yes, that's correct. For example, we don't know how to get this input from user, right? But it's fairly easy. I suggest you post the video after this lecture and try to Google this and find out about how to do this input thing. Let me even give you a hint. This is called TextField. You can find this under Library. 

So, remember how we dragged buttons from the library in the first section. That's how you do that. You can just try to quickly Google how to use TextFields in Swift iOS and you can find about all these operations. And don't worry if you cannot do that on your own or don't worry if you don't want to do that. I'm going to be explaining this and I'm going to be explaining a lot more during these next three lectures. But this will be a good chance for us to practice what we have been learning so far, so that we're going to go and build the worst calculator ever has been made in the history of world. So, let's stop here and continue in the next lecture.