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Introduction to Computer Science and Computational Thinking — HS Computer Science practice questions

26 multiple-choice questions and 15 flashcards on Introduction to Computer Science and Computational Thinking, about 17% of the HS Computer Science bank. Every one carries a written rationale.

Written and maintained by Nick Burton · last updated 2026-08-22 · how we write and review questions

What this chapter covers

Introduction to Computer Science and Computational Thinking is one of 13 chapters in CoStudy's HS Computer Science (Intro) bank, and it holds 26 of the bank's 150 multiple-choice questions — roughly 17% of the total. That proportion is not arbitrary: chapters follow the certifying body's published exam outline, and the number of questions in each is set by that domain's published weight, so the share of your practice time this chapter takes matches the share of the real exam it accounts for.

Studying by chapter is worth doing once you have a diagnostic score. A single overall percentage tells you whether you are close; it does not tell you which domain is dragging. Working a weak chapter in isolation, and re-testing it in isolation, is the fastest way to move a score that has stalled — and it is why the mock exams in CoStudy report by domain rather than as one number.

Free Introduction to Computer Science and Computational Thinking practice questions

10 questions drawn from this chapter, with the full rationale shown — the controlling principle behind the right answer, and why each wrong option tempts and fails.

What is the primary purpose of comments in source code?

  1. To execute additional commands
  2. To make code human-readable by explaining intent, without affecting execution
  3. To increase performance
  4. To encrypt the code

Answer: B — To make code human-readable by explaining intent, without affecting execution

Comments are ignored by the compiler/interpreter and serve as in-code documentation for human readers.

An IP address uniquely identifies a:

  1. Person on the internet
  2. Device on a network
  3. Website's content
  4. Programming language

Answer: B — Device on a network

An IP address (IPv4 or IPv6) identifies a network interface for routing purposes.

Open-source software is best characterized by:

  1. Being free of all bugs
  2. Source code available for anyone to view, modify, and distribute, typically under a license like MIT, GPL, or Apache
  3. Being illegal to sell
  4. Being owned by the U.S. government

Answer: B — Source code available for anyone to view, modify, and distribute, typically under a license like MIT, GPL, or Apache

Open-source means freely accessible source code with permissive (e.g., MIT) or copyleft (e.g., GPL) licensing — it can still be sold or supported commercially.

A 'bug' in software typically refers to:

  1. A virus
  2. A defect causing the program to behave incorrectly
  3. A hardware failure
  4. A documentation error

Answer: B — A defect causing the program to behave incorrectly

Bugs are programming defects — errors that produce incorrect behavior. The term originates from a moth found in an early relay computer.

In most programming languages, what does '==' typically do?

  1. Assigns a value to a variable
  2. Compares two values for equality and returns a boolean
  3. Adds two numbers
  4. Defines a function

Answer: B — Compares two values for equality and returns a boolean

`==` is the comparison operator; `=` is typically assignment (in C-family languages and Python).

What does HTML stand for?

  1. HyperText Markup Language
  2. High-Tech Modern Language
  3. Hyperlink and Text Management Layer
  4. Home Tool Markup Language

Answer: A — HyperText Markup Language

HTML is the standard markup language for creating web pages.

Which is an example of a high-level programming language?

  1. Assembly
  2. Machine code
  3. Python
  4. Binary

Answer: C — Python

Python is high-level (abstract, human-readable). Assembly and machine/binary code are low-level, closer to hardware.

Which of the following best defines an algorithm?

  1. A programming language
  2. A finite, well-defined sequence of steps that solves a problem or completes a task
  3. A hardware component
  4. A type of computer virus

Answer: B — A finite, well-defined sequence of steps that solves a problem or completes a task

An algorithm is a step-by-step procedure with a defined termination — the foundation of all computation.

Big-O notation describes:

  1. The exact runtime in seconds
  2. The asymptotic upper bound on an algorithm's growth in time or space relative to input size
  3. The number of bugs in code
  4. The memory address of a variable

Answer: B — The asymptotic upper bound on an algorithm's growth in time or space relative to input size

Big-O characterizes how an algorithm's resource usage scales as input grows — e.g., O(1), O(log n), O(n), O(n log n), O(n²).

Which data structure follows Last-In-First-Out (LIFO) order?

  1. Queue
  2. Stack
  3. Linked list
  4. Hash table

Answer: B — Stack

Stacks: last element added is first removed (push/pop). Queues are FIFO (enqueue/dequeue).

Introduction to Computer Science and Computational Thinking flashcards

4 cards from the 15 in this chapter.

RAM vs storage?

RAM: temporary, fast, volatile. Storage (SSD/HDD): permanent, slower.

What is computer science?

Study of computation, automation, information. Includes programming, but broader.

Hardware vs software?

Hardware: physical (CPU, RAM). Software: programs that run on hardware.

Boolean values?

True or False. Used in conditions and logic.

Practise the full chapter

These are a sample. The full Introduction to Computer Science and Computational Thinking chapter runs 41 items with per-chapter progress tracking, on the web and in the iOS app.

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