Solve problems finding a missing part when one part and the whole is known
Lesson details
Learning outcome
I can solve problems finding 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 parts.
- Use the sentence, the whole is ___ and one part is ___ so the other part must be ___
- Notice the smaller the number being partitioned, the fewer the number of combinations.
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 is one of the parts that cannot be seen.
Common misconception
Children may confuse the part and the whole, or 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
Part-part-whole models can continue to be used to record and justify answers to problems. Use part-part-whole models in different orientations and with different numbers of parts for children to use to see objects partitioned in different ways.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Is 3 the whole or a part?
Q2.How many cubes are in the missing part?
Q3.What is the missing part?
Q4.What is the missing part?
Q5.Match the picture to the correct part-part-whole model.
Q6.Which part-part-whole model is showing Aisha’s counters correctly partitioned?
Assessment exit quiz
6 Questions
Q1.What is missing – one of the parts or the whole?
Q2.Aisha thinks the missing part will be 3. Is this correct?
Q3.Lucas thinks the missing part will be 5. Is this correct?
Q4.Lucas thinks the missing part will be the same for all of these. Is he correct?
Q5.Aisha has clapped 3 times. How many more claps does she need to do to make the whole correct?
Q6.Lucas will nod his head 5 times and has already nodded it twice. Which part-part-whole model is showing this correctly?
To help you plan your 1 maths lesson on: Solve problems finding 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: Solve problems finding 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.