Creative Development
Program purpose, collaboration, iterative design
Goal: recognise a creative development problem from its wording, carry out the governing method, and check that the result is reasonable.
Simulate the decision-making
Prepare for the timed AP Computer Science Principles test.
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Question 1Unit
Generated AP Computer Science Principles question
AP Computer Science Principles coverage and review map
Connect every question to the exact skill it rehearses. Work through the units in order, then return to any topic that still needs a hint or a second attempt.
Data
Binary, compression, abstraction, data analysis
Goal: recognise a data problem from its wording, carry out the governing method, and check that the result is reasonable.
Algorithms and Programming
Variables, lists, procedures, algorithms, simulation
Goal: recognise a algorithms and programming problem from its wording, carry out the governing method, and check that the result is reasonable.
Computer Systems and Networks
Internet protocols, fault tolerance, parallel computing
Goal: recognise a computer systems and networks problem from its wording, carry out the governing method, and check that the result is reasonable.
Impact of Computing
Bias, privacy, security, digital divide
Goal: recognise a impact of computing problem from its wording, carry out the governing method, and check that the result is reasonable.
AP Computer Science Principles questions with worked answers
These 8 questions are printed in full on this page and are drawn across all 5 course units. Nothing here is generated on the fly. Cover the options, solve each one on paper, and only then open the worked answer to compare your method with the one shown.
Question 1: How many different values can be represented with 6 bits?
- 64
- 36
- 12
- 32
Show the worked answer
- Each bit is either 0 or 1, so every extra bit doubles the count.
- With n bits there are 2^n possible values.
- 2^6 = 2 x 2 x 2 x 2 x 2 x 2.
- That equals 64 values, from 0 through 63.
Answer: 64
Question 2: A 2,000 KB image is compressed to 400 KB. What percent of the original size was removed?
- 80%
- 20%
- 40%
- 5%
Show the worked answer
- The amount removed is 2,000 - 400 = 1,600 KB.
- Compare that with the original size.
- 1,600 / 2,000 = 0.8.
- So 80% was removed and 20% remains.
Answer: 80%
Question 3: Binary search runs on a sorted list of 1,000 items. What is the largest number of comparisons it may need?
- 10
- 500
- 1,000
- 100
Show the worked answer
- Binary search cuts the remaining list in half after each comparison.
- After k comparisons at most 2^k items can be distinguished.
- 2^9 = 512, which is not enough, and 2^10 = 1,024, which is.
- So at most 10 comparisons are needed.
Answer: 10
Question 4: A loop that runs n times contains another loop that also runs n times. How does the running time grow?
- In proportion to n squared
- In proportion to n
- In proportion to 2 to the power n
- It does not depend on n
Show the worked answer
- The inner loop finishes n steps for every single pass of the outer loop.
- The outer loop makes n passes.
- Total steps are n x n.
- That is n squared, so doubling n makes the program take about four times as long.
Answer: In proportion to n squared
Question 5: IPv4 addresses use 32 bits. About how many distinct addresses is that?
- About 4.3 billion
- About 4.3 million
- About 32 billion
- About 65,536
Show the worked answer
- The number of addresses is 2 raised to the number of bits.
- 2^32 = 4,294,967,296.
- That is about 4.3 billion.
- It is not enough for today's devices, which is why IPv6 uses 128 bits.
Answer: About 4.3 billion
Question 6: Why does splitting a message into packets that travel by different routes make the Internet more reliable?
- If one path fails, packets can still reach the destination another way.
- Packets travel faster than a whole message would.
- Packets do not need to be reassembled at the destination.
- Each packet is automatically encrypted by the router.
Show the worked answer
- Routing is decided hop by hop, not fixed in advance.
- Because there are many possible paths, a broken link is not fatal.
- This redundancy is what makes the network fault tolerant.
- Speed and encryption are separate issues, and packets do have to be reassembled in order at the end.
Answer: If one path fails, packets can still reach the destination another way.
Question 7: A facial recognition tool works less accurately for some skin tones because of its training data. What issue is this?
- Algorithmic bias inherited from the data
- A hardware failure in the camera
- A network latency problem
- A data compression error
Show the worked answer
- The program learns patterns from the examples it is given.
- If some groups appear rarely in the training set, the model has less to learn from about them.
- The resulting uneven accuracy is called algorithmic bias.
- Fixing it means changing the data and the testing, not the camera or the network.
Answer: Algorithmic bias inherited from the data
Question 8: A program gives a wrong result for one specific input but runs without crashing. What kind of error is this?
- A logic error
- A syntax error
- A runtime error
- An overflow error
Show the worked answer
- A syntax error stops the program from running at all.
- A runtime error stops the program part way through, with a crash or an exception.
- Here the program runs to the end and simply produces the wrong answer.
- That is a logic error, best found by testing with inputs whose answers you already know.
Answer: A logic error
Which unit each printed question belongs to
Use this map after marking your work. If two misses share a unit, review that unit before starting a generated set.
| Question | Unit | What it asks | Answer |
|---|---|---|---|
| 1 | Data | How many different values can be represented with 6 bits? | 64 |
| 2 | Data | A 2,000 KB image is compressed to 400 KB. What percent of the original size was removed? | 80% |
| 3 | Algorithms and Programming | Binary search runs on a sorted list of 1,000 items. What is the largest number of comparisons it may need? | 10 |
| 4 | Algorithms and Programming | A loop that runs n times contains another loop that also runs n times. How does the running time grow? | In proportion to n squared |
| 5 | Computer Systems and Networks | IPv4 addresses use 32 bits. About how many distinct addresses is that? | About 4.3 billion |
| 6 | Computer Systems and Networks | Why does splitting a message into packets that travel by different routes make the Internet more reliable? | If one path fails, packets can still reach the destination another way. |
| 7 | Impact of Computing | A facial recognition tool works less accurately for some skin tones because of its training data. What issue is this? | Algorithmic bias inherited from the data |
| 8 | Creative Development | A program gives a wrong result for one specific input but runs without crashing. What kind of error is this? | A logic error |
How the generated AP Computer Science Principles sets are created
The 8 questions above are fixed and checked. The generator at the top of the page is different: it writes fresh questions with AI from the course and unit information shown here, then the application checks each one for a complete prompt, four choices, one keyed answer, and an explanation. Generated questions are original practice—not official or released exam questions—and AI can still make mathematical mistakes. Verify a disputed answer with the stated method, your course materials, or the MathGPT solver, and follow the site's academic-integrity guidance.
Questions about this AP Computer Science Principles course test
What does this page cover?
It covers all 5 AP Computer Science Principles units listed above.
When can I see correct answers and explanations?
Submit the full test first. The result screen then shows every response, the correct answer, and the explanation so you can review each miss.
How long is each section of the AP Computer Science Principles exam?
End-of-course multiple choice: 2 hours, 70 questions. Create Performance Task: Through-course, Program plus written responses.
Which AP Computer Science Principles sections allow a calculator?
Rules change from section to section. End-of-course multiple choice: no calculator. Provided during the exam: Exam Reference Sheet. Create Performance Task: not applicable. Practise each section under its own rule.
Which AP Computer Science Principles units does this test cover?
All five: Creative Development, Data, Algorithms and Programming, Computer Systems and Networks, Impact of Computing. Study first: Create-task evidence capture.
What should I check first when I review a missed AP Computer Science Principles question?
Written responses that describe what the program does instead of how it works. Reference your own code by line and name, and explain the logic.
What should I do with a missed question?
Classify the miss as a definition, setup, calculation, interpretation, or timing error. Re-solve it from a blank page, then use the MathGPT tutor for a hint or method check.