OCR J277 Computer Science 2.1 Tracing Algorithms

OCR J277 GCSE Computer Science 2.1.2 lesson: trace tables, purpose of algorithms, syntax and logic errors, in Exam Reference Language. 30 slides.

A complete, ready-to-teach lesson for OCR GCSE Computer Science (J277) 2.1.2: using trace tables, working out the purpose of an algorithm, and identifying common errors.

What’s included (30 editable slides)

• Learning objectives and a retrieval Do Now with answers
• What a trace table is, and why it is used
• OCR Exam Reference Language key: =, ==, !=, for … next, while … endwhile, if … then … endif, MOD and DIV
• Fully worked trace table example, with a five-step “how to” guide
• “Your Turn” while loop trace, designed to catch the classic off-by-one mistake
• Visual inspection: six patterns that give away an algorithm’s purpose
• “Spot the Purpose”, “Trace It to Find the Purpose” and “Try Different Inputs” tasks with answers
• Finding Errors: syntax errors vs logic errors
• "Spot the Errors" task: two algorithms, each with one syntax error and one logic error, with answers
• Green, amber and red practice tasks with full answer slides
• Exam-style questions with a mark scheme

Teacher notes on every slide, including misconceptions and teaching suggestions.

All algorithms are written in OCR Exam Reference Language, exactly as students will see them in the exam. This is lesson 4 of 6 in the OCR J277 2.1 Algorithms unit, also available as a complete bundle.