Explain how adjusting the minuend can make mental calculation easier
Lesson details
Learning outcome
I can explain how adjusting the minuend can make mental calculation easier.
Key learning points
- If you increase the minuend the difference increases by the same amount.
- If you decrease the minuend the difference decreases by the same amount.
- Partitioning the minuend can simplify the calculation.
Keywords
Minuend - The minuend is the number being subtracted from.
Subtrahend - A subtrahend is a number subtracted from another.
Adjust - When you adjust you make a change to a number. This is done to make a calculation easier to solve mentally.
Inverse - The inverse is the opposite or reverse operation. For example, subtraction is the inverse operation of addition.
Common misconception
Pupils may be eager to use columnar written methods for larger integers and decimals instead of considering the values and using an efficient strategy.
Emphasise the importance of trying different mental methods so that pupils aren't reliant on written methods that prevent them from fully grasping the underlying structure of additive problems.
Teacher tip
In the second lesson cycle a pictogram is used. Consider when your pupils last interpreted a pictogram; pre-teaching this representation may lead to more success within the lesson.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.In the following equation, which number is the difference?
38 − 12 = 26
Q2.Solve the following calculation mentally by adjusting the minuend and subtrahend.
157 − 32 =
Q3.Solve the following calculation mentally using unitisation.
= 290 − 120
Q4.Solve the following calculation mentally by adjusting the subtrahend and then the difference.
1,050 − 902 =
Q5.Solve the following calculation using a mental strategy.
= 211 − 97
Q6.7,261,000 − 11,000 =
Assessment exit quiz
6 Questions
Q1.Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend.
153 − 36 =
Q2.Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend
= 269 − 46
Q3.Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend.
2,887 − 44 =
Q4.Find the missing number in the equation below by adjusting the minuend to match the ones digit of the subtrahend.
1,567 − 59 =
Q5.Find the missing number in the equation below by adjusting the minuend.
3,084 − 0.46 =
Q6.Find the missing number in the equation below by adjusting the minuend.
= 967,000 − 35,000
To help you plan your 6 maths lesson on: Explain how adjusting the minuend can make mental calculation easier, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 6 maths lesson on: Explain how adjusting the minuend can make mental calculation easier, 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 subtraction problems unit, dive into the full primary maths curriculum, or learn more about lesson planning.