Chapter4 : The Coordinate System

Hi everyone! Welcome to our last chapter, the coordinate system! In this chapter, you will be introduced to the cartesian coordinate system! First, do you remember the number line we made with our arms in the first chapter? We used them to help us find different numbers, both positive and negative! Well, in this chapter, we will be using two of those lines, in the shape of a cross. This will be helpful when we have to find a pair of numbers instead of only one. But in this video, let’s just learn what we call the two lines! The first line, which can only go left and right, is called the x-axis. This line works the same as the number line we looked at before. When we want to find the number 3, for example, we take three steps to the right, and when we want to find the number -2, we take two steps to the left. The second line, which only goes up and down, is called the y-axis! For this line, the direction going up is the positive numbers, and the direction going down is the negative numbers. So if we want to find the number 4, we would take four steps up, and when we want the number -3, we would take 3 steps down from our starting point. Here, note that the starting point, or zero, for both of the lines is the same. It is the point where the two lines meet, which will be the center of the cross they make. To better understand this, let’s do a quick exercise. I’ll be giving you a letter, either x and y, a number, either positive or negative, and a dance move each time. The letter will tell you which axis you will be moving in, the number will tell you how many steps and in which direction you will travel. The dance move will tell you how you will travel to your destination. For example, if I say x, 6, skip, you will skip 6 steps to your right since the x axis is the line that goes left and right. Got it, Okay. Here’s the first command. x, 3, stomp! Perfect! Now, let’s try another one. y, 2, tip-toe! Great! Last one: y, -4, hop! You got it!

Hi everyone! Today, we will learn how to plot points. Remember, in the last video, we learned how to find numbers on the x-axis and the y-axis. Today, we will learn how to put them together! When given a point on the coordinate plane, the point will have two numbers separated by a comma, inside a parenthesis. It looks like this: . Here, the first number is the number on the x-axis, and the second number is the number on the y-axis. To better understand this, let’s do a quick exercise. Grab a partner, and stand together at the imaginary zero, which will be the center of the room you are in.  Your partner will be in charge of the x-axis, and you will be in charge of the y-axis. So when I give you a point, your partner will travel to the first number and you will travel to the second number. Ready? (3, 4)! For this point, your partner should have travelled three steps to the right and you should have travelled four steps up! Did you get it? Okay, from here, we will learn how to combine the two numbers into one single point. To do this, you and your partner will both walk towards each other in a straight line. But here’s the rule. For you who is in charge of the y axis, you can now only move left and right. And your partner, who is in charge of the x axis, can now only move up and down.  Like this: . And now, The place that you two meet is the point that (3,4) represents. Let’s try another example. What about (-2, 1)? . Your partner will move 2 steps to the left and you will move 1 step up. Now try and meet each other! Here is the point (-2,1).

Hi everyone! Today, we will be learning about the four quadrants. Imagine that your floor has x -axis and y-axis. Then there will not only be two lines on the floor, but the floor would be split up into four parts! One, two, three, four! In math, these four parts each have a special name. The part on the top right is called the first quadrant. The top left section is called the second quadrant. The bottom left section is called the third quadrant, and the bottom right section is called the fourth quadrant. To better understand this, let’s try a quick dance exercise. I will give you a number, from one to four, and a dance move. The number will show which quadrant you will be in, and the dance move will be what you will do in that quadrant. For example, if I say 3, turn, you will run to the bottom left part of the room and turn! Ready? 2, jump! 4, roll! 3, slide! 1, freestyle! You got it!  Now, let’s see if we can tell which quadrant a point is in. With a partner, you will do the same thing as we did in the last video. When I give you a point, both of you will travel in your axis, and then walk in straight lines to meet at a single point. But, from there, you will have to find out which quadrant you are in. If you think you two met at the first quadrant, you will jump one time; if you two met at the second quadrant, jump two times; if it is the third quadrant, jump three times, and if it is the fourth quadrant, jump four times. For example, let’s say I give you the point (-2, 3). Your partner will walk two steps to the left and you will walk three steps up. From there, you will travel left and right, and your patner will travel up and down, until you two meet! Where is it? It’s the top left corner, so it’s the second quadrant, which means that we will jump twice! Now, try on your own. (3, -5). (-1,-4). You got it!