Year 1 - Maths
Find a missing part when one part and the whole is known
Composition of numbers 0 to 5
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will revisit how numbers are represented cardinally and ordinally. They will partition 1 - 5 in different ways, find a missing part when one part and the whole are known and explore one more and one less with numbers to five.
Lesson Summary
You will learn to find the missing part when the other part and the whole is known.
Key Notes
- 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.
Vocabulary To Learn
- 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 Mistakes To Avoid
- Children may add the whole and one part to find the missing part.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
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.
2. Use this key word in a maths sentence and explain it clearly. 'Partition'
Partition means to split up a whole into parts. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children may add the whole and one part to find the missing part. Correction: Encourage the use of the stem sentence ___ is the whole, ___ is a part and ___ is a part, to reinforce what the numbers represent.
More Lessons In This Unit
- Explain that numbers can represent how many objects there are in a set Study Guide
- Ordinal numbers show the position of an object in relation to another Study Guide
- Partition numbers one to five in different ways Study Guide
- Partition the numbers one to five in a systematic way Study Guide
- Show one more and one less than a number using representations Study Guide
- Show one more and one less than a number using representations and describe this accurately Study Guide
- Solve problems finding a missing part when one part and the whole is known Study Guide
- Solve problems using a bar model to represent a whole partitioned into two parts Study Guide
- Use a bar model to represent a whole partitioned into two parts Study Guide
Browse all guides in the Year 1 Maths guide library.