FeedBase2

FeedBase2 is a free browser game for learning and practicing 4-bit binary numbers. Convert between decimal values 0–15 and their binary forms (for example, 2 is 0010).

Choose Classic (catch binary), Reverse (catch decimal), or Quiz mode, then pick Easy, Normal, or Hard difficulty. Track your score and streak, enable answer hints, and play on mobile with on-screen controls. Install it as a progressive web app for offline play.

Binary conversion chart: decimal to binary reference image. Source code on GitHub.