Add three addends efficiently
Lesson details
Learning outcome
I can add three addends efficiently.
Key learning points
- 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.
Keywords
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 misconception
Children unable to understand that addends can be swapped but the sum will remain the same.
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.
Teacher tip
It is much more obvious that we can change the order of the addends in the context of aggregation. For example, children can see much more easily that: 3 + 1 + 4 = 1 + 3 + 4. In the second LC, we encourage independence, asking the children to note which addends to add together first.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is the sum of the three addends?
Q2.Look at each expression and match to the correct description.
less than 10
equal to 10
greater than 10
Q3.What will the third addend be to make the expression sum to 10?
+ 7
+ 5
+ 3
+ 1
Q4.Match the double fact to the correct answer.
12
8
6
10
Q5.Which equations represent the part-part-whole model?
Q6.Laura has been adding three addends by combining different pairs. Match each starting expression to her new equation.
5 + 3 = 8
8 + 1 = 9
5 + 5 = 10
4 + 7 = 11
Assessment exit quiz
6 Questions
Q1.True or false.
The order of the addends can be changed to make the addition easier.
Q2.The image shows Aisha's strategy for adding three addends. What strategy did she use?
Q3.Lucas used this strategy to add the three addends.
Order the steps taken in his strategy
Q4.Which step has been taken in solving this equation?
Q5.Match the expression to the equation that could be used to calculate the sum.
8 + 2 = 10
5 + 5 = 10
6 + 4 = 10
Q6.Solve the equations using an efficient strategy.
8
10
11
9
To help you plan your 2 maths lesson on: Add three addends efficiently, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 2 maths lesson on: Add three addends efficiently, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 1 maths lessons from the Calculating within 20 unit, dive into the full primary maths curriculum, or learn more about lesson planning.