Year 3 - Maths
Count forwards and backwards within 3-digits
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 count forwards and backwards using 3-digit numbers.
Key Notes
- Place value helps us count on and back in 10s and 100s.
- Place value helps us to know which digits change as we cross the 100s or 10s boundaries.
- The 1s and 10s digits don't change when you add a 100 to or subtract 100 from a 3-digit number.
Vocabulary To Learn
- 100s boundary: The 100s boundary is the point at which the numbers change into 100s numbers or from one set of hundreds to another.
- Pattern: A pattern is a repeated set of numbers, shapes or objects.
Common Mistakes To Avoid
- Pupils may struggle to cross 100s boundaries when adding 10s.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Place value helps us count on and back in 10s and 100s. Place value helps us to know which digits change as we cross the 100s or 10s boundaries.
2. Use this key word in a maths sentence and explain it clearly. '100s boundary'
The 100s boundary is the point at which the numbers change into 100s numbers or from one set of hundreds to 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 struggle to cross 100s boundaries when adding 10s. Correction: Base ten blocks can help with this concept. It also helps if children's attention is drawn towards the patterns in the number system.
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
- Estimate the position of 3-digit numbers on unmarked number lines Study Guide
- Ordering sets of 3-digit numbers 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.