This introduction covers Why Round Numbers? 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 1 of 6 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
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.
Practice questions for Rounding & Estimation
Round 4.673 to 1 decimal place.
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.
Quick recall flashcards
Estimation
Round each number to 1 s.f., then calculate
Rounding Rule
Look at the next digit: 0-4 round down, 5-9 round up