This set covers the whole of Python transition and execution: mapping pseudocode into Python, indentation and branches, kinds of error, the safe runtime and exam-year labels. Questions run from easier to harder, and all are original.
Trace each one on paper before opening the answer. Afterwards, check with the Python reasoning sandbox and the restricted pseudocode trace trainer. The mistake log and retest queue is a good place to record anything you got wrong.
Questions
1. Write the Python for these two lines.
Total ← 0
Total ← Total + 5Show answer
total = 0
total = total + 5The arrow ← becomes =. After both lines, total holds 5.
2. Write Python for: IF Age >= 16 THEN OUTPUT "Senior" ENDIF.
Show answer
if age >= 16:
print("Senior")The condition ends with a colon, and the print line is indented. The text in quotes stays exactly the same.
3. What is output?
def f(n):
total = 0
for i in range(1, n + 1):
total = total + i
return total
print(f(4))Show answer
range(1, 5) gives 1, 2, 3, 4. Total goes 1, 3, 6, 10. Output: 10.
4. What is output?
for i in range(3):
print(i * 2)Show answer
range(3) gives 0, 1, 2, so the values printed are 0, 2 and 4, on three lines. Output: 0, 2, 4.
5. Give the result of band(70), band(40) and band(39).
def band(mark):
if mark >= 70:
return "High"
elif mark >= 40:
return "Middle"
else:
return "Low"Show answer
70 >= 70 is True, so High. 40 fails the first test, passes >= 40, so Middle. 39 fails both, so Low.
6. Find the syntax error.
def double(x)
return x * 2Show answer
The def line is missing its colon. Corrected: def double(x):. Python cannot start the program until this is fixed.
7. This function should give the average of two numbers. What does average(4, 10) return, what should it return, and what kind of error is it?
def average(a, b):
return a + b / 2Show answer
Division comes first: 10 / 2 = 5, then 4 + 5 = 9.0. The correct average is (4 + 10) / 2 = 7.0. It is a logic error, because it runs without a message. Fix: return (a + b) / 2.
8. What is output, and what would the output be if count = count + 1 were moved back to line up with if?
count = 0
for n in [3, 8, 5, 10]:
if n > 4:
count = count + 1
print(count)Show answer
As written, 8, 5 and 10 are greater than 4, so the output is 3. Moved back to the level of if, the line runs for every item, so the output becomes 4.
9. What is output? Then say what happens if the line n = n * 2 is removed.
n = 1
while n < 20:
n = n * 2
print(n)Show answer
n goes 1, 2, 4, 8, 16, 32. At 32 the test 32 < 20 is False, so the output is 32. Without n = n * 2, n never changes, the test stays True and the loop never ends. A runtime with a time limit stops it.
10. A question says “write the algorithm in pseudocode”. You usually code in Python. What should you write, and where would you check which notation your exam year expects?
Show answer
Write pseudocode in Cambridge style, because the question asks for it. Check the syllabus for your own exam year on the Cambridge IGCSE Computer Science 0478 page, and ask your exam centre which syllabus you are entered for. Advice written for another year is unchecked until confirmed.
11. This does not run in the browser sandbox. Why, and how do you fix the exercise?
marks = open("marks.txt").read()Show answer
The runtime has no file access. Put invented data in the program: marks = [72, 45, 50, 38, 91]. The algorithm you are testing stays the same.
If you got these wrong
| What went wrong | Go to |
|---|---|
Translation, range ends, = versus == (Q1 to Q4) | Map an algorithm into a restricted Python function |
| Branch order, indentation, loop placement (Q5, Q8) | Test indentation and branch structure |
| Error types and wrong results (Q6, Q7) | Distinguish a syntax error from a wrong result |
| Endless loops, files, sandbox limits (Q9, Q11) | Use a safe browser runtime |
| Notation and exam year (Q10) | Keep 2029 Python-only guidance separate |
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