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Scientific calculators are a wonderful invention, but theyre only as good as the people who use them. If you often get an unexpected or ridiculous result when you press the enter button, this free course, Rounding and estimation, is for you. Learn how to do a calculation correctly and get the right answer every time.
After studying this course, you should be able to:
- round a given whole number to the nearest 10, 100, 1000 and so on
- round a decimal number to a given number of decimal places or significant figures
- use rounded numbers to find rough estimates for calculations
- use a calculator for decimal calculations involving +, −, × and ÷, giving the answer to a specified accuracy (e.g. decimal places or significant figures) and checking the answer by finding a rough estimate
- check the answers to calculations by ensuring that the correct calculation has been done, in the correct order.
- Current section: Introduction
- Learning outcomes
- 1 Rounding
- 1.1 Rounding in daily life
- 1.2 Rounding whole numbers
- 1.3 Rounding in general
- 1.4 Rounding decimals
- 1.5 Significant figures
- 1.6 Significant figures for numbers less than one
- 2 Estimation
- 3 Checking your answers
- 3.1 Have I done the right calculation?
- 3.2 Have I used the correct order for my calculation?
- 3.3 Have I given due consideration to units of measurement?
- 3.4 Did I make a rough estimate to act as a check?
- 3.5 Does the answer make sense in the real world?
- 3.6 Additional practice
- 4 OpenMark quiz
- Keep on learning
Study this free course
Enrol to access the full course, get recognition for the skills you learn, track your progress and on completion gain a statement of participation to demonstrate your learning to others. Make your learning visible!
Rounding and estimation
For many calculations you use a calculator. The main aim of this course is to help you to do this in a sensible and fruitful way. Using a calculation to solve a problem involves four main stages:
Stage 1: working out what calculation you want to do;
Stage 2: working out roughly what size of answer to expect from your calculation;
Stage 3: carrying out the calculation;
Stage 4: interpreting the answer – Does it agree with the rough estimate? Does it make sense in terms of the original problem?
This course focuses on Stages 2 and 4.
This OpenLearn course provides a sample of level 1 study in.
This free course includes adapted extracts from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Mathematics Education courses or view the range of currently available OU Mathematics Education courses.
Copyright & revisions
Originally published: Friday, 10th June 2011
Last updated on: Wednesday, 23rd March 2016
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements and our FAQs section.
- This site has Copy Reuse Tracking enabled - see our FAQs for more information.
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