IGCSE Computer Science 0478: How to Complete a Trace Table Without Losing Marks
By Zaheer | Updated 14 October 2026 Disclosure: I created the IGCSE Computer Science 0478 Mission Control app mentioned at the end and sell it on Gumroad. Everything in this post is free to use without it. This is independent study material, not affiliated with Cambridge or any exam board. Trace tables are some of the most predictable marks in IGCSE Computer Science. You are given a short algorithm and some input values, and you fill in a table to show what happens at every step. Students lose marks here not because the idea is hard, but because of small slips: a missing starting value, a loop run once too many times, or an output written in the wrong place. This post shows a reliable method, a worked example, the five most common mistakes, and three tasks to try yourself. What a trace table is for A trace table records the value of each variable as an algorithm runs, so you can see what it does without running it on a computer. Examiners use it to check that you can fo...