Mathematics
Boolean Algebra and the Design of Logical Circuits
Quick fact
Every single operation inside a computer—from adding two numbers to loading a web page—ultimately reduces to a few basic Boolean operations (AND, OR, NOT) performed on binary values, and these operations are physically realized with transistors on chips.
Why this is interesting
Every time you tap a screen or play a video, your device is making billions of electrical decisions based on a simple algebra you already know: true and false. But how does a string of 0s and 1s become a functioning computer?