The opposite of reading coordinates: you are given a pair (x, y) and you have to mark the point on the grid in the right place. With practice this becomes very fast.
Three-step routine
Start at the origin (0, 0) — where the x-axis and y-axis cross.
Move x squares to the right along the x-axis. (If x is 0, stay where you are.)
From there, move y squares up. (If y is 0, stay where you are.)
Mark the point with a dot or a small cross.
The mnemonic is the same as for reading: along the corridor, then up the stairs. Across first, then up.
A worked example
Plot the point (3, 4).
From (0, 0), go 3 squares right. You're now at (3, 0).
From there, go 4 squares up. You're at (3, 4).
Mark a dot.
Plot the point (0, 5).
x is 0, so don't move sideways at all.
Go 5 squares straight up the y-axis.
Mark a dot at (0, 5).
Plot the point (6, 0).
x is 6, go 6 squares right.
y is 0, don't go up at all.
Mark a dot on the x-axis at (6, 0).
Plotting many points to draw a shape
Often a question gives you a list of coordinates and asks you to join them up to draw a shape. The trick is to plot all the points first, then join them in order with a ruler.
Plot the points (1, 2), (5, 2), (5, 6) and (1, 6). Join them in order and back to the start. What shape do you get?
(1, 2) — one right, two up.
(5, 2) — five right, two up.
(5, 6) — five right, six up.
(1, 6) — one right, six up.
Joining (1,2) → (5,2) → (5,6) → (1,6) → (1,2): a rectangle, 4 squares wide and 4 squares tall — actually a square (since the width equals the height).
Plotting tips
Use a sharp pencil. A fat dot covers two or three gridlines and is hard to read later.
Use a small cross (×) instead of a dot for clearer marks.
Label the points with their letter or coordinate. (1, 2) might be labelled "A" if the question gives names.
Use a ruler when joining points with straight lines.
Common mistakes
Counting up first, then across. That swaps x and y. Always across first.
Going past zero. If x = 0, don't go anywhere sideways — start straight up. If y = 0, don't go up.
Marking between gridlines. Coordinates like (3, 4) are integers, so the dot sits exactly on the intersection of the gridlines, not in the middle of a square.
A puzzle
A square has corners at (2, 1), (5, 1), (5, 4) and (2, 4). What is the length of one side?
The side from (2, 1) to (5, 1) goes from x = 2 to x = 5 — that's a distance of 3 squares. So one side is 3 units long.
