Year 8 - Maths
Rounding integers to one significant figure
Estimation and rounding
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
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 integers to one significant figure.
Key Notes
- It is possible to use rounding and place value to know the size of a number without knowing the actual number.
- The first non-zero digit of a number is the first significant figure.
- You can identify the place value of the first significant figure.
- A number can be located on a number line and numbers to 1 significant figure either side of it represented.
- Any integer can be rounded to one significant figure and a number line can help with this.
Vocabulary To Learn
- Significant figure: Significant figures are the digits in a number that contribute to the accuracy of the number. The first significant figure is the first non-zero digit.
- 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
- Assuming all zero digits are not significant.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
It is possible to use rounding and place value to know the size of a number without knowing the actual number. The first non-zero digit of a number is the first significant figure.
2. Use this key word in a maths sentence and explain it clearly. 'Significant figure'
Significant figures are the digits in a number that contribute to the accuracy of the number. The first significant figure is the first non-zero digit. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Assuming all zero digits are not significant. Correction: Within the lesson there are many examples where some zeros are significant. Relate significance back to the communication of accuracy and that some digits are significant as they preserve the place value of other digits.
More Lessons In This Unit
- Checking by estimating Study Guide
- Checking understanding of rounding Study Guide
- Degrees of accuracy Study Guide
- Estimating numerical calculations Study Guide
- Inequality notation to express error Study Guide
- Overestimating vs underestimating Study Guide
- Problem solving with estimation and rounding Study Guide
- Rounding decimals to significant figures Study Guide
- Rounding errors Study Guide
- Rounding integers to significant figures Study Guide
- Rounding to any number of decimal places Study Guide
- Rounding to three decimal places Study Guide
- Securing understanding of rounding Study Guide
- Truncating Study Guide
- Using inequality notation for errors in calculations Study Guide
Browse all guides in the Year 8 Maths guide library.