Year 2 - Maths
Add three addends efficiently
Calculating within 20
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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 add 3 addends. They will use a strategy such as finding 2 addends to total 10 or 2 numbers to bridge though 10.
Lesson Summary
You will learn to add three addends efficiently.
Key Notes
- The order of the addends can be changed to make the addition easier
- The sum will be the same whichever pair of addends we add first.
- Finding a known fact or double to add first can be more efficient.
- Strategies used to be efficient might be different for everyone.
Vocabulary To Learn
- Addends: Any of the numbers that are added together.
- Efficient: Not wasting time or effort. An efficient strategy is one we can carry out easily.
- Strategy: A plan or method to achieve a specific goal.
Common Mistakes To Avoid
- Children unable to understand that addends can be swapped but the sum will remain the same.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The order of the addends can be changed to make the addition easier. The sum will be the same whichever pair of addends we add first.
2. Use this key word in a maths sentence and explain it clearly. 'Addends'
Any of the numbers that are added together. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children unable to understand that addends can be swapped but the sum will remain the same. Correction: Use a number line to explore commutativity in a situation where it looks less obvious as this will show children the different structures but also different starting pints but the end pint will remain the same.
More Lessons In This Unit
- Add and subtract two numbers that bridge through 10 Study Guide
- Add three addends Study Guide
- Add three addends efficiently by finding two addends that total 10 Study Guide
- Add two numbers that bridge through 10 Study Guide
- Calculate the difference Study Guide
- Calculate the difference in different contexts Study Guide
- Calculate the difference when information is presented in a bar chart Study Guide
- Calculate the difference when information is presented in a pictogram Study Guide
- Compare the number of objects in two sets or difference between two measures. Study Guide
- Explain that the addends can be added in any order Study Guide
- Explain what the difference is between consecutive numbers Study Guide
- Use a 'First, then, then, now' story to add three addends Study Guide
- Use knowledge of calculating within 20 to solve problems Study Guide
- Use knowledge of calculating within 20 to solve problems involving statistics Study Guide
Browse all guides in the Year 2 Maths guide library.