Rounding decimals to significant figures
Lesson details
Learning outcome
I can round decimals to a required number of significant figures.
Key learning points
- Numbers bigger than 1 with decimals places can be rounded to significant figures.
- When working with numbers smaller than one it is important to carefully identify the first significant figure.
- Once the first significant figure is identified you can find any significant figure.
- It is important to know when zeros are and are not significant.
Keywords
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 misconception
Assuming all zero digits are not significant.
Designing questions that contain zero digits in a variety of positions.
Teacher tip
Using MWB ask pupils to down decimals with a given number of decimal places and a particular digit in given significant figure position. E.g. Write down a decimal with 5 digits after the decimal point and 3 as the second significant figure.
Licence
Lesson video
Loading...
Prior knowledge starter quiz
6 Questions
Q1.In the number 56 072, the 7 is the significant figure.
Q2.Select the numbers that have 3 as the third significant figure.
Q3.Select all the numbers which have zeros that are not needed to preserve the place value of other digits.
Q4.Match each number to the correct statement.
5 is the second significant figure
5 is the fourth significant figure
5 is the first significant figure
5 is the fifth significant figure
5 is the third significant figure
Q5.Round 9452 to 2 significant figures.
Q6.Round 8096.564 to 3 significant figures.
Assessment exit quiz
6 Questions
Q1.The first figure is the first non-zero digit in a number.
Q2.Match each number to the correct statement.
5 is the first significant figure
2 is the first significant figure
4 is the first significant figure
7 is the first significant figure
3 is the first significant figure
Q3.Round 0.00754 to 2 significant figures.
Q4.Round 0.006083 to 3 significant figures.
Q5.Round 0.0495 to 2 significant figures.
Q6.Round 0.03098 to 3 significant figures.
To help you plan your 8 maths lesson on: Rounding decimals to significant figures, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 8 maths lesson on: Rounding decimals to significant figures, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 3 maths lessons from the Estimation and rounding unit, dive into the full secondary maths curriculum, or learn more about lesson planning.