Learning pack · IGCSE handout

Accuracy

What's in this pack: printable worksheet PDF, matching answers PDF (IGCSE / Secure–Stretch practice). Bounds and appropriate accuracy: a measurement rounded to a given unit lies within half a unit either way.

Resources at the top · full summary · videos with short notes below.

🎒 Resources in this pack

Jump straight to the printable files, or scroll to the summary and videos.

Scaffolded Learning Sheet — attempt the worksheet, then use the Answers for a full written solution.

📝 Open Learning Sheet ✅ Open answers 🎬 More topic videos (6)📖 Full summary

Files: 27_accuracy_handout.pdf · 27_accuracy_handout_answers.pdf

Full topic summary

Bounds and appropriate accuracy: a measurement rounded to a given unit lies within half a unit either way.

Key learning points

If $x$ is given to nearest unit $u$ , error is $\pm\tfrac12 u$ .
Lower/upper bounds feed into calculations for maximum/minimum results.
Choose sensible accuracy for the context (money → 2 d.p., etc.).

Worked example 1 — Bounds

A length is $12.4\,\mathrm{cm}$ to 1 d.p. Find the error interval.

Working

12.35\le L<12.45

Half a unit in the last digit.

Worked example 2 — Upper bound calculation

Sides $4.2$ and $3.1$ (1 d.p.). Upper bound of rectangle perimeter?

Working

2(4.25+3.15)=14.8

Use upper bounds of both sides.

Worked example 3 — Truncation

Truncate $3.89$ to 1 d.p.

Working

3.8

Truncation cuts digits; rounding would give $3.9$ .

🎬 Topic videos

Math Antics - Integer Multiplication & Division
Math Antics · 10 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Introduction to Integers
Eddie Woo · 5 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Adding and Subtracting Integers (Applying operations to integers and visualising with Number line)
Eddie Woo · 12 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Subtracting with integer chips | Integers: Addition and subtraction | 7th grade | Khan Academy
Khan Academy · 6 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Adding with integer chips | Integers: Addition and subtraction | 7th grade | Khan Academy
Khan Academy · 4 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.
Adding and Subtracting Negative Numbers
Maths Genie · 9 min
Lower Secondary classroom-friendly explainer. Scaffold→stretch friendly; use with mixed-ability groups.

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