Trace Tables Worksheet: OCR GCSE J277

A GCSE trace tables worksheet for OCR J277 2.1.2: a method, a worked example and four algorithms to trace. 20 marks in 40 minutes, with a full mark scheme.

Students learn an eight-step method for completing a trace table, follow a worked example of a for loop, then trace four algorithms written in OCR Exam Reference Language, one to a page. Every trace comes with its table printed: the columns are given, and there are more rows than the trace needs.

What’s inside (8 pages, PDF and editable Word)

• Six student pages (pages 1 to 6): the method, the worked example with an explanation of every row, and Traces 1 to 4.
• A full mark scheme (pages 7 and 8), with every completed trace table and the mark points for each. It starts on an odd page, so a double-sided print keeps it off the back of a student sheet.

The four traces

1. Selection: an if-else that decides which message to display.
2. A while loop with MOD and DIV, then a mark for saying what the algorithm calculates.
3. An array read by a for loop, then a mark for saying what the algorithm finds.
4. A string read one character at a time.

Traces 1 and 2 use a Line number column, and Traces 3 and 4 use the one-row-per-pass layout, so students meet both styles OCR prints.

Why it works in a real classroom

• A slip is not punished twice. The output mark follows through from the student’s own table, and in Trace 1 a wrong branch costs one mark, not two.
• It marks what examiners mark. Line numbers carry no marks, and repeated values and an extra loop-counter row are accepted.
• Editable. The Word version is included, so you can change a name, a number or a scenario to suit your class.
• Nothing to set up. Print, hand out, collect. There is nothing to install and nothing to log in to.

You need: one copy of pages 1 to 6 per student. Keep pages 7 and 8 back; a cut line marks where the mark scheme starts.

Good for: a lesson on algorithms, homework after teaching 2.1.2, a cover lesson, or Year 11 revision before Paper 2.

Made by a practising computing teacher. The answers are written out in full and checked. If you use it, a review helps other teachers find it.