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S3 ICT: Algorithms and Flowcharts (Paper 3: challenge)
S3 ICT: Algorithms and Flowcharts (Paper 3: challenge)
S3 ICT algorithms and flowcharts paper three, challenge: ten questions on the three control structures, causes of infinite loops, nested loops with a moving inner bound, binary search limits and overlapping counts.
Direct answers Answers in order: sequence selection and iteration, the control variable is never updated, the rounded rectangle, ten, a total of 25 with mean 5, six comparisons, two tests, eleven comparisons, 9, and a sequential program needs no diamond.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S3 ICT: Algorithms and Flowcharts |
| Level | S3 |
02 Questions (10 items)
- FoundationWhich three basic control structures make up any flowchart?
- FoundationWhat is the most common cause of a program that never stops?
- FoundationWhich symbol marks the start and the end of a flowchart?
- IntermediateWith an outer FOR i = 1 TO 4 and an inner FOR j = 1 TO i, how many inner rounds run in total?
- IntermediateWhat are the total and the mean of 3, 4, 5, 6 and 7?
- IntermediateHow many comparisons are needed to find the largest of seven values?
- ChallengeTesting from two upwards, how many tests decide whether 9 is prime?
- ChallengeHow many comparisons does binary search need at most on 1 024 sorted items?
- ChallengeWith count = 0 and FOR i = 1 TO 20 adding one when i is a multiple of 3 or 5, what is the final count?
- Error redoA student says every flowchart must contain a decision diamond. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Sequence, selection and iteration | Every program logic is built by combining these three structures. |
| 2 | A loop condition that always holds because the control variable is never updated inside the loop | If the condition stays true and the variable never changes, the loop runs forever. |
| 3 | The rounded rectangle, also drawn as an oval | The terminal symbol appears only at the start and the end. |
| 4 | Ten | One plus two plus three plus four is ten, since the inner bound follows the outer counter. |
| 5 | A total of 25 and a mean of 5 | The mean of five consecutive integers is the middle one and five times five is twenty five. |
| 6 | Six | Assume the first is the largest and compare each of the other six once. |
| 7 | Two tests, for 2 and for 3 | Nine leaves a remainder with two but divides exactly by three, so it is not prime. |
| 8 | Eleven | Halving ten times leaves a single candidate that still needs one confirming test. |
| 9 | Nine | Six multiples of three and four of five overlap at fifteen, so six plus four minus one is nine. |
| 10 | A purely sequential program runs top to bottom and needs no diamond | A diamond is added only where branching is needed, otherwise the chart no longer matches the program. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
An algorithm is a finite and unambiguous list of steps; flowcharts use a diamond for decisions and a parallelogram for input or output, combined through sequence, selection and iteration.Tutor Registration →
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