Rounding & Estimation

MathematicsAQAEdexcelGCSEUnit: Number
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The basics

Why Round Numbers?

Why Round Numbers?

Your calculator says π = 3.141592653589793... but you can't write that in every answer! Rounding gives us sensible, usable numbers. Whether it's 2 decimal places for money or 3 significant figures for science, rounding is essential.
Rounding rules - decimal places, significant figures, the 5-or-more rule
Exam tip

Earn the mark scheme marks

Common Mistakes

  • WRONG: Counting leading zeros as significant (0.005 has 1 s.f., not 3)
  • WRONG: Forgetting trailing zeros matter in s.f. (3.50 has 3 s.f., not 2)
  • RIGHT: For estimation, round to 1 s.f. to make calculation easy

Now try it yourself

Quiz · Question 1 of 13

Round 4.673 to 1 decimal place.

Tap an answer to check it

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