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Year 8 - Maths

Rounding to any number of decimal places

Estimation and rounding

Unit Summary

This unit helps pupils understand rounding to different decimal places, and significant figures. Pupils will also learn how to truncate numbers and understand the contexts in which these skills are useful. The unit ends will an exploration of rounding and inequality errors.

Lesson Summary

You will learn to round numbers to any number of decimal places.

Key Notes

  • Numbers with any number of decimal places can be represented on a number line.
  • Any number can be rounded to a given number of decimal places.
  • It is possible to identify the most suitable number of decimal places from the context.
  • It can be useful to think about what the biggest and smallest values of a number rounded in context were.

Vocabulary To Learn

  • Round: To change a number into another number that is approximately the same value but is easier to work with. E.g. round 561 to the nearest 10 is 560.

Common Mistakes To Avoid

  • Pupils think that repeated rounding gives the correct answer.

3 Quick Questions (With Answers)

1. Solve this in steps: explain the method from this lesson and why each step matters.

Numbers with any number of decimal places can be represented on a number line. Any number can be rounded to a given number of decimal places.

2. Use this key word in a maths sentence and explain it clearly. 'Round'

To change a number into another number that is approximately the same value but is easier to work with. E.g. round 561 to the nearest 10 is 560. Use this word when showing your method, then check your final answer is reasonable.

3. Spot and fix this common maths mistake.

Mistake: Pupils think that repeated rounding gives the correct answer. Correction: Use a number line to support pupils' understanding. Locate the number to be rounded on the line and identify the critical values.

More Lessons In This Unit

Browse all guides in the Year 8 Maths guide library.