2210_w20_PM_23 — 2020 Oct-Nov Computer Science 2210 PM 2 Variant 3 · Cambridge CAIE O Level

Not understanding library routines like DIV and ROUND

“Few candidates understood the purpose of DIV and ROUND. Candidates who understood the library routines were able to give a suitable example.”— 2210 Paper 2, May/June 2023

How to fix: Learn every pseudocode library routine in the syllabus insert: DIV (integer division, e.g. 7 DIV 2 = 3), MOD (remainder, e.g. 7 MOD 2 = 1), ROUND (rounds to specified decimal places), RANDOM, LENGTH, UCASE, LCASE, SUBSTRING. For each, memorise what it does, its syntax, and write a one-line example you can recall in the exam.

Using programming language syntax instead of pseudocode

“Candidates are advised to ensure that the style of pseudocode used matches the syntax of the pseudocode defined within the syllabus for this course.”— 2210 Paper 2, May/June 2023

How to fix: The syllabus pseudocode guide is the definitive reference. Use UCASE() not .upper(), use LENGTH() not len(), use SUBSTRING() not slicing. When a question says 'write in pseudocode', marks are lost for Python/Java syntax. Print the pseudocode reference from the syllabus and practise converting between your preferred language and pseudocode.

Confusing verification with validation

“A significant number of candidates incorrectly selected the option that stated verification made sure that a value entered is correct.”— 2210 Paper 2, October/November 2023

How to fix: Verification = checking that data has been entered or transferred ACCURATELY (e.g. double-entry of a password, visual check, parity bit on transmission). Validation = checking that data is REASONABLE (e.g. range check, type check, format check, length check, presence check, check digit). Memorise one example of each. A common trap: 'is the data correct?' is too vague — verification confirms it matches the original input/source, not that it is factually correct.