Rounding summary

Key learning points

• Decimal places: count digits after the point.
• Significant figures: count from the first non-zero digit.
• Estimation: round to 1 s.f. then calculate.

Worked example 1 — Decimal places

Round $7.846$ to 1 decimal place.

Working

Look at the second decimal digit (4).

Worked example 2 — Significant figures

Round $0.004582$ to 2 significant figures.

Working

Count from the first non-zero digit.

Worked example 3 — Estimation

Estimate $48.2\times19.6$ by rounding to 1 s.f.

Working

1 s.f. estimation checks calculator answers.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.