NumberKey Facts

The Key Rule

Part of Rounding & EstimationGCSE Mathematics

This key facts covers The Key Rule within Rounding & Estimation for GCSE Mathematics. Revise Rounding & Estimation in Number for GCSE Mathematics with 13 exam-style questions and 6 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 5 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 2 of 5

Practice

13 questions

Recall

6 flashcards

The Key Rule

Look at the NEXT digit:

• 0, 1, 2, 3, 4 → Round DOWN (keep the digit the same)

• 5, 6, 7, 8, 9 → Round UP (add 1 to the digit)

Keep building this topic

Read this section alongside the surrounding pages in Rounding & Estimation. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Rounding & Estimation

Round 4.673 to 1 decimal place.

  • A. 4.6
  • B. 4.7
  • C. 4.67
  • D. 5.0
1 markfoundation

A student says '3.50 and 3.5 are exactly the same number so they have the same number of significant figures.' Explain why the student is wrong.

2 marksstandard

Quick Recall Flashcards

Rounding Rule
Look at the next digit: 0-4 round down, 5-9 round up
Estimation
Round each number to 1 s.f., then calculate

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