Inequality notation to express error
I can calculate possible errors expressed using inequality notation a ≤ x < b.
Inequality notation to express error
I can calculate possible errors expressed using inequality notation a ≤ x < b.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- When given a rounded number you can say what the biggest and smallest values of the unrounded number could have been.
- You can use $$a ≤ x < b$$ notation to express the range of values the unrounded number could have taken.
Keywords
Range - A range of values where every value in the range estimates to the given value.
Error interval - An error interval for a number $$x$$ shows the range of possible values of $$x$$. It is written as an inequality $$a ≤ x < b$$
Common misconception
Incorrect use of the error interval i.e $$a ≤ x ≤ b$$ or writing the error interval as $$a ≤ x > b$$
As a check, encourage students to round the upper limit interval by the degree of accuracy to see if it evaluates to the rounded number. Also, draw a number line to show the meaning of $$a ≤ x > b$$ and allow students to see the error.
To help you plan your year 8 maths lesson on: Inequality notation to express error, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 8 maths lesson on: Inequality notation to express error, 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.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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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.