ICS3U exam review: Grade 11 Computer Science practice questions and exam rules

The daily Grade 11 Computer Science (ICS3U) paper has 8 original questions worth 25 to 35 marks. It is practice for programming fundamentals, data types, algorithms, searching and sorting, binary and hexadecimal, Boolean logic, and security and ethics. Its CPU and networking questions go further than ICS3U usually does, and its code may not be in the language your class uses.

How the ICS3U final evaluation counts in 2026-27

In Grade 11 in Ontario, your final mark is now 65% classroom work, a 25% final evaluation, and 10% attendance and participation. For computer studies, that 25% is split into a 10% written exam, written in your board's exam period, and a 15% culminating task that your teacher sets. ICS3U has no prerequisite. These figures come from the Ministry of Education's September 2026 update to Growing Success.

What's on the ICS3U exam: the strands

• A. Programming concepts and skills: data types and expressions, control structures and subprograms.
• B. Software development: the software development life cycle, designing, testing and debugging.
• C. The computing environment.
• D. Computers and society: environmental and ethical issues, emerging research and careers.

ICS3U practice questions with answers

We wrote these for this page. The code is in Python; the ideas carry over to whatever language your class uses.

1. Data types and expressions. What do 17 // 5, 17 % 5, 17 / 5 and int("7") + 3 give in Python? Answer: 3 (whole-number division), 2 (the remainder), 3.4 (true division gives a float) and 10 (the string is converted to an int first). "7" + 3 without int() would raise a type error.

2. Control structures. What does this print?

count = 0
for n in [3, 8, 12, 7, 10]:
    if n % 2 == 0:
        count = count + 1
print(count)

Answer: 3. It counts the even numbers: 8, 12 and 10. Trace loops with a table of each variable's value per pass. Try your own in the Code Editor.

3. Number systems. Convert binary 101101 to decimal and to hexadecimal. Answer: 32 + 8 + 4 + 1 = 45. Split into groups of four from the right, 0010 1101, which is 2D in hex. Try a conversion from our Binary, Hexadecimal and Decimal course, then press Mark.

4. Searching. How many comparisons does a linear search need in the worst case for a list of 50 items, and when is that worst case? Answer: 50, when the item is last or not in the list at all. Binary search is faster but needs the list sorted first. Watch both in the Algorithm Visualiser.

5. Subprograms. Write a function that returns the average of a list of numbers, and say what it should do with an empty list.

def average(values):
    if len(values) == 0:
        return 0
    return sum(values) / len(values)

Answer: checking for an empty list first avoids dividing by zero. Returning 0 is one choice; your teacher may want an error message instead, so state what you chose. Good test cases include an empty list, one item and negative numbers.

Use the daily paper as a practice exam

1. Open today's ICS3U paper and work to the suggested time, 30 to 35 minutes.
2. Rewrite any code answers in the language your class uses.
3. Treat CPU and networking questions as extra.
4. Mark it and note which strand each lost mark belongs to.

Common ICS3U mistakes

• Mixing up / and // in Python.
• Adding a string to a number without converting it.
• Off-by-one loop ranges: range(5) runs 0 to 4.
• Not testing edge cases such as empty input.
• Using binary search on an unsorted list.

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