A coordinate system is a grid that is formed by two number lines crossing each other at the point where the number zero appears on both lines. This intersection is called the origin. A coordinate system looks like this:

The $x$-axis is also called *the first axis*, while the $y$-axis is called the *the second axis*.

You will come across coordinate systems both in math at school and in daily life. Coordinate systems are a tool that help you know where things are located.

Think About This

**Look at the coordinate system with the positive numbers on the figure. How do you think you read a point in the grid? **

The answer is revealed further down on the page.

A point in the grid is called a coordinate. Every coordinate consists of one value from the first axis and one value from the second axis (see figure).

Below, you can see a coordinate system with points.These points are named after letters in the alphabet. This is how you find the coordinates of a point:

Rule

- 1.
- Put your finger on the point, then drag your finger straight down until you hit the first axis. Write down the number that is now under your finger.
- 2.
- Put your finger back on the point, then drag your finger straight left until you hit the second axis. Write down the number that is now under your finger.
- 3.
- The coordinates should look like this: $(x,y)$. You have to replace the x with the number you found on the first axis. You have to replace the y with the number you found on the second axis.

Think About This

**Can you read the coordinates of the different points above? **

$A=(1,1)$ | $B=(3,1)$ | $C=(2,3)$ |

$D=(4,3)$ | $E=(1,5)$ | $F=(3,10)$ |

$G=(8,7)$ | $H=(5,7)$ | $I=(7,4)$ |

$J=(7,7)$ | $K=(0,4)$ | $L=(6,0)$ |

$A=(1,1)$ | $B=(3,1)$ | $C=(2,3)$ | $D=(4,3)$ |

$E=(1,5)$ | $F=(3,10)$ | $G=(8,7)$ | $H=(5,7)$ |

$I=(7,4)$ | $J=(7,7)$ | $K=(0,4)$ | $L=(6,0)$ |

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