Solve equations involving the subtraction of two-digit numbers
Lesson details
Learning outcome
I can solve equations involving the subtraction of two-digit numbers.
Key learning points
- The known part can be partitioned into tens and ones before subtracting to help subtract two-digit numbers.
- Known facts and the partitioning of numbers can be used to help solve missing number equations.
Keywords
Partition - To split a whole up into parts - a piece or section of a whole.
Part - A piece or section of a whole.
Common misconception
Children may partition both the whole and the parts when subtracting two 2-digit numbers. They need to know to avoid this because it gives an incorrect answer when subtracting numbers which bridge 10
You may wish to explore further examples which do and do not reach the correct answer, articulating why this is the case and coming to the generalisation that, when subtracting, only one part needs to be partitioned into tens and ones.
Teacher tip
This lesson involves building upon prior knowledge to subtract two 2-digit numbers. Children are encouraged to manipulate individual numbers in equations in order to build confidence and mental flexibility to work efficiently.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Izzy wants to solve the equation 87 − 6 = ? Which is the most efficient strategy to use?
Q2.Andeep has £78 and he buys a unicorn. Which known fact should he use to calculate how much money he has left?
Q3.Match each equation to say which digit will change when it is solved.
The ones digit will change from 7 to 3
The tens digit will change from 7 to 3
Q4.Match the equations which will leave the same part remaining.
47 − 30 − 2 = ?
47 − 3 − 20 = ?
47 − 5 − 30 = ?
Q5.Fill in the missing number to solve the equation 76 − 35 = ?
Q6.Choose an equation to represent the number line.
Assessment exit quiz
6 Questions
Q1.Match the expressions which have the same value.
89 − 51
69 − 37
75 − 15
Q2.Which number is missing in the equation? 74 − 34 = 74 − − 4
Q3.Which equation is represented by the number line.
Q4.Find the missing part in the bar model.
Q5.How many tens are in the missing part? 47 − _4 = 23
Q6.Find the missing part. 75 − = 31
To help you plan your 2 maths lesson on: Solve equations involving the subtraction of two-digit numbers, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 2 maths lesson on: Solve equations involving the subtraction of two-digit numbers, 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.