Number lines
A coordinate uses a number line in each direction.
Curriculum topic
Coordinates and Movement
Coordinates describe position. A screen is a map made from numbers, and every object needs a way to answer: Where am I?
Scratch coordinate map
x goes sideways. y goes vertically.
The centre gives every point a shared origin: x: 0, y: 0.
+x / right-x / left+y / up-y / downx: 0, y: 0Ax: 140, y: 90Bx: -150, y: 70Cx: -120, y: -80Dx: 160, y: -95
Why it matters
A small idea that returns in larger systems.
Coordinates connect number lines to visible movement. They let students predict where an object will go, define boundaries, compare positions, and debug a map instead of moving sprites by guesswork.
Real-world connection
Maps, screen layouts, robot navigation, drones, and computer vision all need a representation of position. This first topic does not teach those advanced systems; it establishes the idea that returns inside them.
The connection shows where the idea returns; it does not claim every advanced application is taught in this first topic.
Math and logic kernel
The structure beneath the project.
Positive and negative
The sign tells us which side of the origin a point occupies.
Horizontal and vertical
The x value controls left and right; y controls down and up.
Change in position
Distance moved can be described by comparing a before and after value.
Centre and origin
The point x: 0, y: 0 gives the screen a shared reference point.
Small examples
Make one relationship visible at a time.
Known start
Place a player at x: -180, y: -100 for every test.
Horizontal movement
Change x while keeping y unchanged.
Vertical movement
Change y while keeping x unchanged.
Relative clue
Compare two positions to decide left/right and above/below.
Program connections
Where this topic appears.
Active now
Scratch & Game Design
Beginner-friendly programming through original games, animations, simulations, and interactive stories.
Active now
Robotics
Commands, sensors, simple electronics, simulations, and physical systems organized around Sense, Decide, Act.
Available later
Roblox Studio / Lua
A future bridge from visual programming to Lua, 3D objects, events, and larger game systems.
Available later
AI & Smart Machines
A future practical and critical program about patterns, predictions, prompts, limits, and human judgment.
Common mistakes
Useful clues, not reasons to stop.
Changing x instead of y
The character moves sideways when the intended movement was vertical.
Using the wrong sign
A positive change moves in the opposite direction from the one predicted.
Starting from an unknown position
A test gives different results because the sprite was never reset.
Moving forever
The code changes position repeatedly without checking stage boundaries.
Confusing direction with position
Where a sprite faces is not the same as where it is located.
Fixing the symptom
Extra movement blocks hide a problem instead of inspecting the current x and y values.
Lesson and projects
Use the idea inside a working system.
Scratch & Game Design
Complete downloadable pilot
Escape from the Giant Pigeon
Build a fast chase game with known positions, collision rules, win and loss states, and reliable restart behaviour.
Open project
Scratch & Game Design
Computer Lab Project
Grandma's Intergalactic Taxi
Navigate a space taxi between coordinate-based pickups and destinations.
Open project
Scratch & Game Design
Computer Lab Project
Astro-Chicken Rescue
Collect drifting space chickens while tracking several positions and avoiding danger zones.
Open project