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Lessons take about five minutes

Learn computer science, one bite at a time.

Short, game-like lessons that turn bits, binary and the ideas behind every program into things you actually understand. Answer, get instant feedback, build a streak.

Start learning free
See how a lesson works
  • 10 exercises in lesson one
  • 6 exercise types
  • XP and daily streaks
A real question from lesson one.

Answer, check, continue. That is the whole loop.

One question at a time, no walls of text. You find out straight away whether you were right, and why.

Instant feedback, with the reason

Every answer ends with a one-line explanation, so a mistake becomes the part you remember.

Correct!

101 = 4 + 0 + 1 = 5.

Correct answer: A single 0 or 1

A bit is the smallest piece of data a computer stores.

Mistakes come back

Miss a question and it returns at the end of the lesson, so you finish by getting it right.

XP for every lesson

10 XP for finishing, plus 1 for each question you get right first time. A daily streak keeps count of the days you show up.

Six ways to practise, so it never feels like a quiz.

Each lesson mixes them. These are real examples from lesson one.

  • Multiple choice

    What is a bit?

  • True or false

    A byte is made of 8 bits.

  • Match pairs

    2 ↔ 10   3 ↔ 11   4 ↔ 100

  • Fill in the blank

    2 × 2 × 2 = 2³ = ___

  • Tap to order

    Write the number 6 in binary: 1 1 0

  • Type the answer

    What is binary 1111 in decimal?

Unit 1 - available now

How computers count

Start with the smallest idea in computing, the bit, and work up to reading binary numbers in your head.

  • What a bit and a byte are
  • Why computers use two states
  • Counting and converting in binary
  • How many values n bits can hold
Start Bits & Binary

On the way

New units are planned. Create an account and they appear on your path as they ship.

  • Logic gatesPlanned
  • Variables and typesPlanned
  • LoopsPlanned
  • Big-O basicsPlanned

Questions, answered.

Short answers first, as you would expect.

Do I need to know how to code?
No. Unit 1 starts from zero: what a bit is, and why computers count the way they do.
How long does a lesson take?
About five minutes. Lesson one is ten short exercises, plus any you miss, which come back at the end.
Is it free?
Yes. Creating an account and playing the lessons costs nothing right now.
Is my progress saved?
Your XP, streak and finished lessons are saved to your account. A lesson you leave halfway starts again from the first question.
Is there a mobile app?
Duocasts works in your phone's browser today, and iOS and Android apps are planned.

Ready for your first bit?

Make an account, finish one lesson, and see where a five-minute habit takes you.

Create your free account I already have an account

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