Identify knowns and unknowns in addition equations
Lesson details
Learning outcome
I can identify knowns and unknowns in addition equations.
Key learning points
- If the sum is missing, you add the addends.
- If an addend is missing, subtract the other addend from the sum to calculate the missing value.
- When the numbers are close together, add on to find the difference.
Keywords
Addend - An addend is a number added to another.
Sum - The sum is the the total when numbers are added together.
Difference - The difference is the result after subtracting one number from another.
Common misconception
Pupils may confuse the parts and the whole in an equation, especially when there is a missing number.
Bar models are helpful for representing and understanding the parts and the whole. Ensure that pupils understand that minuend and sum both represent a whole. Allow lots of opportunities for pupils to sketch bar models.
Teacher tip
Base ten blocks may be helpful for pupils when subtracting. Number lines representations may also be helpful, especially for comparing the relative size of numbers and understanding whether they are close together or far apart.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which number in this equation is the sum? 100 = 20 + 80
Q2.Which of these are parts in an equation?
Q3.What is the missing sum in this bar model?
Q4.What is the value of the missing part in this bar model?
Q5.What could the missing addends in this bar model be?
Q6.Which equations could be represented by the bar model?
Assessment exit quiz
6 Questions
Q1.Which number represents the difference in this equation? 25 − 15 = 10
Q2.Match the keywords to their meanings.
A number added to another.
The result after subtracting one number from another.
The total when numbers are added together.
Q3.What is the missing part in this bar model?
Q4.What is the value of the missing part in this bar model?
Q5.Which pairs of numbers have a difference of 3?
Q6.How could you calculate the missing part in this bar model?
To help you plan your 3 maths lesson on: Identify knowns and unknowns in addition equations, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 3 maths lesson on: Identify knowns and unknowns in addition 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 2 maths lessons from the Understand additive relationships and apply them to rearrange equations unit, dive into the full primary maths curriculum, or learn more about lesson planning.