Year 1 - Maths
Solve problems finding a missing part when one part and the whole is known
Composition of numbers 0 to 5
Study Hub
Study Guides
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 solve problems finding 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 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.
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 is one of the parts that cannot be seen.
Common Mistakes To Avoid
- Children may confuse the part and the whole, or 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 parts. Use the sentence, the whole is ___ and one part is ___ so the other part must be ___.
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 confuse the part and the whole, or 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
- Find a missing part when one part and the whole is known 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 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.