Debug, Compare, Explain — Year 6 Maths Algorithms Unit

Teach students to investigate how one changed decision or operation affects the outputs of an algorithm. Using a fixed ordered set of rational-number inputs, they predict results, trace both branches, locate the first boundary-case divergence, test a precise revision and explain what their evidence does and does not show.

The five 45–60-minute lessons progress through prediction, systematic finite testing, locating divergence, revision and retesting, and a reasoned final report. Students map each listed input once and stop after the set is complete. Partial traces and physical step cards support access; independent traces and a matched transfer task retain the same learning target.

What's included

• 25-page Unit Plan PDF with contents, a three-page teacher guide, colour display and worked cards, guided/core/transfer practice with matching answers, a 12-card partner challenge and teacher key, rehearsal, an independent assessment with marking guidance, and an evidence rubric.
• Editable PowerPoint presentation: 18 slides.
• Editable PowerPoint quiz: 26 slides, including 12 question-and-explanation pairs.
• Preview PDF.

Learning focus

Specify a finite input domain, ordered steps, yes/no branches, output recording and a stopping rule; compare the effect of a changed condition or operation; explain a boundary case and the limits of a tested claim.

Classroom use

Use across five lessons of approximately 45–60 minutes. Model one trace, practise with partners, then ask students to complete the final assessment independently. Use the rubric to record observed evidence and a targeted next step.

Formats and answers

Digital PDF and editable PPTX. Unit Plan PDF: 25 pages. Presentation: 18 slides. Quiz: 26 slides. Matching worksheet and assessment answer/marking pages are included.

Teacher benefits

The fixed test set makes the comparison repeatable. Paired student and marking pages support specific feedback. The fresh assessment case checks transfer without changing the target skill.

Digital product and licence

Digital download; no physical item is shipped. Check the applicable licence terms at purchase; this listing grants no additional rights.