Find a missing part when one part and the whole is known
Lesson details
Learning outcome
I can find the missing part when the other part and the whole is known.
Key learning points
- Each of the numbers one to five can be partitioned into two or more parts.
- If one part is known, the other part can be found.
- Know what to do when the known part is zero or the missing part is zero.
Keywords
Partition - Partition means to split up a whole into parts.
Part-part-whole model - A part-part-whole model is a pictorial representation that shows the whole and its parts.
Missing part - A missing part means one of the parts that cannot be seen.
Common misconception
Children may add the whole and one part to find the missing part.
Encourage the use of the stem sentence ___ is the whole, ___ is a part and ___ is a part, to reinforce what the numbers represent.
Teacher tip
Essentially children will be subtracting a part from the whole here, but do not use 'subtraction' at this stage (or 'take away' or 'difference') as these are introduced in subsequent units.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Is 5 the whole or a part?
Q2.Is 1 the whole or a part?
Q3.What is the whole?
Q4.Sofia has 1 counter and Jun has 2 counters. Which part-part-whole model is showing their counters?
Q5.Which part-part-whole model is showing Sofia’s objects correctly partitioned?
Q6.Which part-part-whole model is showing Jun’s objects correctly partitioned?
Assessment exit quiz
6 Questions
Q1.How many cubes is the whole made up of?
Q2.Sofia has 3 counters and Jun has 2 counters. Which part-part-whole model correctly shows the parts combining to make the whole?
Q3.How many cubes are in the missing part?
Q4.Sofia thinks the missing part will be 3. Is this correct?
Q5.Jun thinks the missing part will be the same for these part-part-whole models. Is he correct?
Q6.Sofia thinks the missing part will be the same for these part-part-whole models. Is she correct?
To help you plan your 1 maths lesson on: Find a missing part when one part and the whole is known, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 1 maths lesson on: Find a missing part when one part and the whole is known, 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 1 maths lessons from the Composition of numbers 0 to 5 unit, dive into the full primary maths curriculum, or learn more about lesson planning.