The Classroom

Tools, simulators and games

Learn by doing. Everything runs in your browser. Free tools are open to everyone; premium tools open with any unlocked level.

Pseudocode Runner

Write Cambridge pseudocode, run it, and watch a trace table fill in line by line. Perfect for checking your exam answers.

Step through the fetch-decode-execute cycle with a real instruction set. Watch registers and memory change.

Bubble, insertion and selection sort, linear and binary search, animated step by step with a running count.

Type a Boolean expression, get the full truth table, and try the circuits examiners love.

Encrypt and decrypt with a Caesar cipher, break it by trying every key, and see text as binary.

Parity bits, checksums and check digits: flip a bit and see whether it is caught.

Every level has its own guided projects, matched to the stage. Pick your level to start.

Step-by-step lessons to use with the runner, written for each level.