Use known facts and mental strategies to calculate with decimal numbers within and across a whole
Lesson details
Learning outcome
I can use known facts and mental strategies to calculate with decimal numbers within and across a whole.
Key learning points
- If you know that 5 + 2 is equal to 7 then 5 tenths + 2 tenths is equal to 7 tenths so 0.5 + 0.2 = 0.7
- Use known facts and unitising to add tenths.
- Bridging 10 strategies with whole numbers can be applied when the tenths bridge one whole.
Keywords
Number facts - Simple calculations using two numbers are known as number facts. For example 2 + 4 = 6
Bridging - Bridging is a mental strategy which uses addition or subtraction to cross a number boundary.
Common misconception
Pupils record missing part equations incorrectly.
Encourage children to match the equation to a representation identifying which number represents the wholes and which represent parts.
Teacher tip
Use the language of unitising to support pupils each time. For example: I know 10 ones minus 3 ones is equal to 7 ones so 10 tenths minus 3 tenths is equal to 7 tenths.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Tick the number facts that make 10.
Q2.Ten tenths are equal to
Q3.I know 7 − 5 = 2 so 700 − 500 =
Q4.Tick all of the equations that can represent this part-part-whole model.
Q5.I know 12 − 5 = 7 so 120 − 50 =
Q6.What are the missing numbers that the nine would need to be partitioned into to bridge 10 for this example.
Assessment exit quiz
6 Questions
Q1.I know 3 + 6 = 9 so 0.3 + 0.6 =
Q2.I know 8 − 5 = 3 so 0.8 − 0.5 =
Q3.Which of these pairs of numbers sum to make 1?
Q4.Use a known number fact to help you solve: 1 − 0.3 =
Q5.Fill in the missing number for the equation represented by the number line.
Q6.Fill in the missing number: ___ − 0.7 = 0.8
To help you plan your 5 maths lesson on: Use known facts and mental strategies to calculate with decimal numbers within and across a whole, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 5 maths lesson on: Use known facts and mental strategies to calculate with decimal numbers within and across a whole, 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 2 maths lessons from the Compose and calculate with decimals including column addition and subtraction unit, dive into the full primary maths curriculum, or learn more about lesson planning.