Chapter intro: Binary and number bases

Every photo on your phone, every song you have saved, and every message you have ever sent, all of them come down to the same thing underneath. Nothing but switches, and each switch is simply on, or off. This chapter, Binary and number bases, builds that idea up from scratch, and because it is the first chapter in GCSE Computer Science, it is also where the whole subject begins.

Right, here is the whole chapter laid out on your screen, along with two quick things worth knowing before you press play on the first video.

It runs from why computers use binary at all, through converting numbers by hand, into hexadecimal, binary addition, overflow, shifting bits, and finally how a negative number gets represented. Every video in this chapter comes back to the same picture: two states, on or off, combining into longer patterns, until they can hold any number, any letter, or any sound you like.

One practical thing first: every video here carries its own short, searchable code, sitting right beside its title on the list. Take the first teaching video, Why computers use binary: search for ScholaFly C S oh one, oh one, and that exact video comes straight up, no scrolling needed.

The other trick is the thumbs-up sitting on each video: once a topic has properly landed for you, tap it, and that video marks itself as nailed. Anything left without a thumbs-up becomes your natural revision list, and if a topic has not clicked yet, save it to a playlist instead, because plenty of this lands properly on a second watch, days later. And my commitment to you is this: if I've not done a great job teaching something and it's confusing, leave a comment, and I'll have a crack at making a better video.

Next in the chapter: Why computers use binary, search for ScholaFly C S oh one, oh one.

For more, visit scholafly.com, or watch the next video.