Follow variables through a program step by step and predict what happens next.
Coding practice
Debug it before you trust it
Not a syntax tutorial — a bug hunt with real test cases.
The Computer Science Keep skips typing raw syntax and goes straight to computational thinking: trace what a loop or condition actually does, predict the output, then hunt down a bug using test cases and edge cases the same way real debugging works.
No account to start. No child data collected unless a parent signs in for reports.
What you'll practice
Real moves, not a quiz wall
See why a stack, queue, or tree fits one problem better than another.
Use test cases and edge cases to isolate exactly where a program breaks.
Get a feel for Big O and why some approaches slow down as input grows.
Questions parents ask
Before you start
No. The free room opens with no sign-in. A parent can sign in separately to see progress reports — nothing is required to start playing.
No — the room teaches computational thinking (loops, conditions, data structures, debugging) before any specific syntax.
The Computer Science Keep targets roughly grades 4–9, with easier and harder difficulty bands inside the same room.
Not on the free public room. Data is only stored if a parent explicitly signs in to enable progress reports.
Computer Science Keep