20 QUESTIONS · 5 TOPICS · ABOUT 10 MINUTES

Everything on your screen is ones and zeros.

Computer science is the study of what can be computed and how efficiently. Twenty questions on data, algorithms, hardware, networks and theory, no coding required, each explained. No sign-up, nothing saved.

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QUESTION 1 / 20 · DATAEasy

What is 1011 in binary as a decimal number?

What this computer science test covers, in short

Twenty conceptual questions, four in each of five areas: how data is represented, algorithms and complexity, hardware, networks and the internet, and the theory of computation. It checks understanding, not programming skill.

The level is roughly a secondary-school or first-year university course. For code-reading questions, try one of our programming tests instead.

By What's Your IQ · Reviewed 4 Oct 2026
Format
20 multiple-choice questions, 4 options each
Topics
Data, algorithms, hardware, networks, theory
Level
School to first-year university
Coding
None required
Some problems can't be solvedby any computer, everAlan Turing proved in 1936 that no program can decide, for every program, whether it will eventually stop. Question 19 is about it.1
1843The first program. Ada Lovelace published an algorithm for Babbage's unbuilt Analytical Engine.
1936The Turing machine. A simple imaginary machine that defined what "computable" means.1
1945 · 1948Stored programs and information. Von Neumann's design kept programs in memory; Claude Shannon defined the bit as a unit of information.2
1971P vs NP. Stephen Cook formalised the question of whether every quickly checkable problem is also quickly solvable. It's still open.3
  1. Turing, A. M. (1937). On computable numbers, with an application to the Entscheidungsproblem. Proceedings of the London Mathematical Society, s2-42(1), 230–265.
  2. Shannon, C. E. (1948). A mathematical theory of communication. Bell System Technical Journal, 27(3), 379–423.
  3. Cook, S. A. (1971). The complexity of theorem-proving procedures. Proceedings of the 3rd ACM Symposium on Theory of Computing, 151–158.

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