New
New
Year 1
Find a missing part when one part and the whole is known
I can find the missing part when the other part and the whole is known.
New
New
Year 1
Find a missing part when one part and the whole is known
I can find the missing part when the other part and the whole is known.
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Lesson details
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.
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.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), licensed on
Open Government Licence version 3.0
except where otherwise stated. See Oak's terms & conditions (Collection 2).Lesson video
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Starter quiz
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6 Questions
Q1.
Is 5 the whole or a part?
Part
Q2.
Is 1 the whole or a part?
Whole
Q3.
What is the whole?
1
2
3
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?
Exit quiz
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6 Questions
Q1.
How many cubes is the whole made up of?
2
3
4
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?
2
3
4
5
Q4.
Sofia thinks the missing part will be 3. Is this correct?
Yes
Q5.
Jun thinks the missing part will be the same for these part-part-whole models. Is he correct?
No
Q6.
Sofia thinks the missing part will be the same for these part-part-whole models. Is she correct?
Yes