Applying a range of strategies to mentally calculate subtraction

Applying a range of strategies to mentally calculate subtraction

Lesson details

Key learning points

  1. In this lesson, we will use different mental strategies to calculate subtraction such as partitioning, counting on and using known facts.

Licence

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4 Questions

Q1.
What does the word 'efficient' mean?
To do something badly.
To do something slowly.
Correct answer: To do something well without wasting energy.
Q2.
Which of these is not a strategy for adding efficiently?
Changing the order of the addends to make a calculation easier
Correct answer: Finding the difference
Rounding and adjusting
Using doubling and halving
Q3.
When adding 66 and 67 which is an efficient strategy?
Counting on in my head from the largest number
Correct answer: Doubling and adjusting
Drawing out a number line
Q4.
When adding 69 and 81 which would be an efficient strategy?
Doubling and halving
Drawing out a number line
Correct answer: Rounding and adjusting
Using dienes

4 Questions

Q1.
What does the word 'efficient' mean?
To do something badly.
To do something slowly.
Correct answer: To do something well without wasting energy.
Q2.
Which of these is not a strategy for subtracting efficiently?
Correct answer: Changing the order of the addends to make a calculation easier
Finding the difference
Partitioning and subtracting one part
Using known facts
Q3.
When calculating 50 - 48 which is an efficient strategy?
Correct answer: Count on to find the difference
Counting back on my fingers
Drawing out a number line
Partitioning and subtracting
Q4.
When calculating 92 - 57 which would be an efficient strategy?
Counting back on my fingers
Drawing out a number line
Correct answer: Partitioning and subtracting one part

Lesson appears in

UnitMaths / Exploring calculation strategies and place value