Combine tens and ones within equations
Lesson details
Learning outcome
I can combine and partition tens and ones in the context of equations.
Key learning points
- Known strategies can be used to help us prepare for the addition of two 2-digit numbers.
- It is important to be able to calculate mentally before adding two 2-digit numbers.
Keywords
Calculate - To work out an answer, often by adding or subtracting.
Efficiently - Not wasting time or effort. An efficient strategy is one we can carry out easily.
Common misconception
Children may rely on the order of the addends rather than their place value when calculating. They may also default to counting on rather than using known facts.
Refer back to known facts and efficient strategies and model their use throughout, discussing the best strategy to use at each point and why. Model errors that can be made when not adding ones then tens for example, or in counting on in ones.
Teacher tip
This lesson provides a stepping stone to ensure links are made between existing knowledge and knowledge to be developed around adding two 2-digit numbers. It is important that known facts are used rather than inefficient counting strategies to lessen the cognitive load.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Andeep wants to solve the equation 2 + 40 + 50 = ? Which is the most efficient strategy to use?
Q2.Andeep estimates the cost of the items shown. Which of the following is most likely to be accurate?
Q3.For which of the following equations would you use the bridge 10 strategy?
Q4.For which equations would you use the known facts strategy? Tick two.
Q5.Andeep’s items cost £54 Which of the following will be the cost of Izzy’s items?
Q6.Match to show which equations will have the same sum.
37 + 6 =
39 + 2 =
33 + 5 =
Assessment exit quiz
6 Questions
Q1.Use the Base 10 blocks shown to solve the equation.
Q2.Match the expressions which have the same value.
1 + 40 + 3 + 20
4 + 1 + 30 + 20
2 + 10 + 30 + 4
Q3.What is the missing whole in the bar model?
Q4.Tick the correct equation.
Q5.Match the equations to the correct missing addend.
40
20
3
Q6.Which of the digit cards shown would complete the equation?
To help you plan your 2 maths lesson on: Combine tens and ones within equations, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 2 maths lesson on: Combine tens and ones within equations, 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 Addition and subtraction of two 2-digit numbers unit, dive into the full primary maths curriculum, or learn more about lesson planning.