Cambridge and Edexcel both grade pseudocode against a specific style, and small formatting habits cost more marks than most students realize. None of these mistakes are about understanding the logic. They're about how it's written down.
Mixing assignment symbols. Cambridge pseudocode uses ← for assignment, not =. Using = throughout looks like a small thing, but graders are trained to flag it, and it happens on nearly every script.
Forgetting to close loops and conditionals properly. IF... THEN... ENDIF, FOR... NEXT, WHILE... ENDWHILE. Leaving these open, or closing them with the wrong keyword, reads as a structural error even when the logic inside is correct.
Vague variable names. x, temp, a1 don't communicate intent. Examiners can follow studentScore or totalCount far more easily, and clearer naming reduces the chance of losing marks on unrelated questions where they're trying to trace your logic.
Inconsistent indentation. Pseudocode isn't graded like Python, where indentation is required to run. But consistent indentation is how examiners see the structure of your nested loops and conditionals at a glance. Flat, unindented pseudocode makes correct logic look wrong.
Skipping the algorithm design step entirely. Some students jump straight to writing code once they understand the logic. But a large share of IGCSE marks are allocated to the design process itself, not just the final answer, and pseudocode is where that process is shown.
None of these fixes take long to learn. They just take a habit of writing pseudocode formally from day one, rather than treating it as an afterthought before the "real" programming starts.