Use efficient methods to solve subtraction equations
Lesson details
Learning outcome
I can use efficient methods to solve subtraction equations.
Key learning points
- Consecutive numbers always have a difference of 1
- If the whole and the known part in a subtraction equation are consecutive numbers, the missing part will always be 1
- If the known part in a subtraction equation is 1, the whole and the missing part will be consecutive numbers
- When the ones digits in the whole and the known part are the same, the missing part will be a multiple of 10
Keywords
Consecutive - Numbers which follow each other in order, without gaps.
Difference - The result of subtracting one number from another.
Whole - All of something; complete.
Part - A piece or section of a whole.
Common misconception
When writing equations with consecutive numbers, children may write in the order they are counted , e.g. 56-57 = forwards
Give missing number equations and represent them on part-part-whole models and bar models to consolidate understanding of which numbers in the equation represent the whole and the parts.
Teacher tip
For learning cycle 1, ensure representations which draw attention to the linear structure of numbers (e.g. bead strings, Rekenreks, number lines) are used. For learning cycle 2, use representations which highlight the place value of the numbers involved (e.g. Base 10 blocks, images of ten frames).
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.In which of the following equations will you have to bridge 10?
Q2.Which of the following equations is correct?
Q3.Solve the following equation. 43 − 25 =
Q4.Andeep has 76 tickets. He buys the ball. How many tickets does he have left?
Q5.Andeep had 66 tickets. He bought a plane and now he has 23 tickets left. How much did the plane cost?
Q6.Match each equation to the correct answer.
19
52
48
Assessment exit quiz
6 Questions
Q1.Write a subtraction equation to calculate the missing part in this bar model and solve it.
Q2.Which of the following equations will have a difference of 1?
Q3.One of the missing numbers in this equation is 57 Which of the following could be the other missing number? ___ − ___ = 1
Q4.In which of the following equations will the missing part be a multiple of 10?
Q5.Solve the equation. 88 − 58 =
Q6.What is the missing digit in the equation?
To help you plan your 2 maths lesson on: Use efficient methods to solve subtraction equations, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 2 maths lesson on: Use efficient methods to solve subtraction 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.