Finding Your Way with Coordinates

Imagine you have a treasure map. Someone tells you the treasure is buried 'somewhere on the island' — not very helpful! But what if they said 'go 4 steps right, then 3 steps up'? Now you can find it exactly. That is the big idea behind coordinates. They are a pair of numbers that pinpoint any location on a grid. Think about games like Battleship or any map with a grid — coordinates are used everywhere.

A coordinate grid has two lines called axes. The horizontal line going left and right is the x-axis. The vertical line going up and down is the y-axis. The two axes cross at a special point called the origin, which is always (0, 0). A coordinate pair is written like this: (x, y). The first number tells you how far to move along the x-axis (to the right). The second number tells you how far to move up the y-axis. A helpful saying is: 'along the corridor, then up the stairs.' Always go across first, then up. In the first quadrant, both numbers are zero or bigger — so you never go left or down from the origin. To FIND a point: start at (0, 0), count right by the x number, then count up by the y number. Mark the spot. To READ a point already on the grid: count how far right it is from the origin — that is x. Count how far up it is — that is y. Write them as (x, y).