Coordinates

Coordinates describe positions on a grid using ordered pairs. This topic links geometry and algebra, and is essential for linear graphs and distance calculations.

Overview

Coordinates tell you the exact position of a point on a grid.

A coordinate is written as two numbers inside brackets.

\( (x, y) \)

The first number tells you how far to move along the horizontal axis. The second number tells you how far to move up or down the vertical axis.

What you should understand after this topic

  • Read coordinates correctly
  • Plot points on a grid
  • Understand the x-axis and y-axis
  • Understand how the four quadrants work
  • Describe simple movements between points

Key Definitions

Coordinate

A pair of numbers that gives the position of a point.

x-coordinate

The first number. It shows horizontal position.

y-coordinate

The second number. It shows vertical position.

x-axis

The horizontal axis.

y-axis

The vertical axis.

Origin

The point where the axes cross: \( (0,0) \).

Key Rules

x first, y second

Always read coordinates as \( (x, y) \), never the other way round.

Start from the origin

Plot coordinates by moving from \( (0,0) \).

Horizontal before vertical

Move along the x-axis first, then up or down for the y-value.

Negative values matter

Negative x means left, negative y means down.

How to Solve

Step 1: Understand the axes

The coordinate plane is made of two perpendicular axes. The x-axis runs horizontally and the y-axis runs vertically. They meet at the origin.

Origin = \( (0,0) \)
Exam tip: Always check which axis is which before reading coordinates.
Coordinate grid showing x axis, y axis, origin and quadrants

Step 2: Read coordinates in the correct order

Coordinates are always written as \( (x, y) \).

Move along the x-axis first (left or right).
Then move along the y-axis (up or down).
Exam tip: Across first, then up.

Step 3: Plotting a point

To plot \( (-3,5) \):

Move 3 left (negative x-value).
Move 5 up (positive y-value).
Mark the point clearly.

Step 4: Quadrants

The grid is divided into four quadrants.

Exam tip: Learn the sign pattern β€” this is frequently tested.

Quadrant 1

\( (+,+) \)

Quadrant 2

\( (-,+) \)

Quadrant 3

\( (-,-) \)

Quadrant 4

\( (+,-) \)

Step 5: Reading a point from a graph

Start at the point and read across first, then up or down.

Across gives the x-coordinate.
Up or down gives the y-coordinate.

Step 6: Distance on a grid

You can measure horizontal and vertical distances using coordinates.

Horizontal distance = difference in x-values.
Vertical distance = difference in y-values.
For diagonal distance, use Pythagoras’ theorem.

Step 7: Midpoint of a line

The midpoint is the point exactly halfway between two coordinates.

\( \text{Midpoint} = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right) \)
Exam tip: Average x-values and y-values separately.

Example Questions

Edexcel

Exam-style questions focusing on reading coordinates from a grid.

Edexcel

The point A is shown on the coordinate grid.

A 6 -2

Which number is the x-coordinate of point A?

Edexcel

The point A is shown on the coordinate grid.

A 6 -2

Which number is the y-coordinate of point A?

AQA

Exam-style questions focusing on identifying quadrants.

AQA

The point (4, -3) is shown on the grid.

(4,-3) Q1 Q2 Q3 Q4

In which quadrant is the point?

AQA

Plot the point (-5, 2).

(-5,2)

Which quadrant is this point in?

OCR

Exam-style questions focusing on reasoning with coordinates and movement.

OCR

The point (0, 4) lies on the coordinate grid.

(0,4)

Explain why this point is not in any quadrant.

OCR

A point moves from (-2, 1) to (3, -2).

(-2,1) (3,-2)

Describe the movement.

Exam Checklist

Step 1

Check that you are reading the coordinate as \((x,y)\).

Step 2

Move horizontally first, then vertically.

Step 3

Watch carefully for negative numbers.

Step 4

Use the signs of x and y to identify the correct quadrant.

Most common exam mistakes

Wrong order

Reading \((x,y)\) as \((y,x)\).

Wrong direction

Going right instead of left, or up instead of down.

Quadrant confusion

Forgetting the sign pattern in each quadrant.

Axis points

Points on the axes are not inside a quadrant.

Common Mistakes

These are common mistakes students make when working with coordinates in GCSE Maths.

Writing coordinates in the wrong order

Incorrect

A student writes a point as (y, x) instead of (x, y).

Correct

Coordinates are always written in the order (x, y), where x is the horizontal movement and y is the vertical movement.

Moving vertically before horizontally

Incorrect

A student moves up or down first when plotting a point.

Correct

Always move horizontally first (x-direction), then vertically (y-direction) when plotting coordinates.

Misunderstanding negative x-values

Incorrect

A student moves right when the x-value is negative.

Correct

Negative x-values mean move to the left on the coordinate grid, while positive x-values move to the right.

Misunderstanding negative y-values

Incorrect

A student moves up when the y-value is negative.

Correct

Negative y-values mean move down the grid, while positive y-values move upwards.

Mixing up the quadrants

Incorrect

A student places a point in the wrong quadrant.

Correct

Each quadrant has a specific sign pattern: (+,+), (-,+), (-,-), (+,-). Use this to check the correct position of a point.

Try It Yourself

Practise plotting and interpreting coordinates on the Cartesian plane.

Questions coming soon
Foundation

Foundation Practice

Read and plot coordinates, identify quadrants and interpret simple movements.

Question 1

Write the coordinates of point A.

A y x

Games

Practise this topic with interactive games.

Games coming soon.

Frequently Asked Questions

What are coordinates?

Points on a grid given as (x, y).

What is the origin?

(0,0) on the grid.

How do I plot points?

Move along x-axis first, then up or down y-axis.