Solve addition calculations mentally by using known facts
Lesson details
Learning outcome
I can solve addition calculations mentally by using known facts.
Key learning points
- If I increase this addend by __ then the sum will increase by the same amount.
- If I decrease this addend by __ then the sum will decrease by the same amount.
- A balance beam can represent unequal expressions or inequalities.
Keywords
Equation - An equation is used to show that one number, calculation or expression is equal to another.
Adjustment - An adjustment is a change to a number using either subtraction or addition.
Whole - The whole is all the parts or everything, the total amount.
Part - A part is a piece or section of the whole.
Common misconception
Pupils may find it hard to understand that recalculating the adjusted part is an unnecessary step.
Display two sets of workings side-by-side. In the 1st, show the adjusted part being recalculated. In the 2nd, show it without recalculating the part. Pupils will hopefully see that the solution emerges from both.
Teacher tip
Number bonds to 100 and 1,000 are very useful here and always worth practising. They could be used as a basis for early morning work or you could verbally challenge the children as they're lining up for assembly. Remember, success breeds motivation!
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is the missing number in this part-whole model?
Q2.What is the missing number in this part-whole model?
Q3.In digits, write the number being represented by the place value counters.
Q4.What is the complement to 1 of 0.654?
Q5.What is the complement to 1 for 0.654?
Q6.What is the unknown in this equation?
435,000 + = 425,000 + 16,000
Assessment exit quiz
6 Questions
Q1.What does an equation show?
Q2.What known fact is most helpful in completing the following calculation in your head? 134 + 5 = 139
Q3.Find the missing number mentally (use jottings if needed).
= 67.24 + 0.76
Q4.Find the missing number mentally (use jottings if needed).
15.65 + 0.34 =
Q5.Find the missing number mentally (use jottings if needed).
68,000 + 232,000 =
Q6.Find the missing number mentally (use jottings if needed). = 456,000 + 31,000
To help you plan your 6 maths lesson on: Solve addition calculations mentally by using known facts, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 6 maths lesson on: Solve addition calculations mentally by using known facts, 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 Use equivalence and compensation to simplify and solve addition calculations unit, dive into the full primary maths curriculum, or learn more about lesson planning.