Year 3 - Maths
Ordering sets of 3-digit numbers
Representing 3-digit numbers, comparing and positioning on number lines
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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 use knowledge of place value to represent a 3-digit number in different ways. They will compare and order 3-digit numbers and position on number lines and unmarked number lines.
Lesson Summary
You will learn to order a set of 3-digit numbers.
Key Notes
- If the 100s digits are different, the numbers can be compared or ordered by looking at the 100s digit.
- If the 100s digits are the same, the numbers can be compared or ordered by looking at the 10s digit.
- If the 100s and 10s digits are the same, the numbers can be compared or ordered by looking at the 1s digit.
Vocabulary To Learn
- Compare: You compare to find out what is the same and what is different. You compare numbers to find out if one is more than or less than another.
- Order: You can order numbers from the smallest to the largest or from the largest to the smallest.
Common Mistakes To Avoid
- Pupils may look at all the digits at once when ordering numbers and this may lead to mistakes.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
If the 100s digits are different, the numbers can be compared or ordered by looking at the 100s digit. If the 100s digits are the same, the numbers can be compared or ordered by looking at the 10s digit.
2. Use this key word in a maths sentence and explain it clearly. 'Compare'
You compare to find out what is the same and what is different. You compare numbers to find out if one is more than or less than another. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may look at all the digits at once when ordering numbers and this may lead to mistakes. Correction: When ordering 3-digit numbers, encourage pupils to compare the 100s digits first and then the 10s digits (and the 1s) afterwards.
More Lessons In This Unit
- Add and subtract to and from a 3-digit number bridging 100 Study Guide
- Comparing and ordering numbers with 1, 2 and 3 digits Study Guide
- Count forwards and backwards in multiples of 2, 20, 5, 50 and 25 Study Guide
- Count forwards and backwards within 3-digits Study Guide
- Estimate the position of 3-digit numbers on unmarked number lines Study Guide
- Partition 3-digit numbers in different ways Study Guide
- Position 3-digit numbers on number lines Study Guide
- Represent a 3-digit number up to 1,000 in different ways Study Guide
- Solve problems by adding and subtracting to or from 3-digit numbers Study Guide
- Solve problems by counting forwards and backwards in multiples of 2, 20, 5, 50 and 25 Study Guide
- Use known facts to add and subtract multiples of 100 within 1000 Study Guide
- Use known facts to add and subtract to and from multiples of 100 Study Guide
- Use known facts to solve problems involving partitioning numbers Study Guide
- Write a 3-digit multiple of 10 as a multiplication equation Study Guide
Browse all guides in the Year 3 Maths guide library.