New
New
Year 6
Solve problems explaining which strategy is most efficient
I can solve problems, explaining which strategy is most efficient.
New
New
Year 6
Solve problems explaining which strategy is most efficient
I can solve problems, explaining which strategy is most efficient.
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Lesson details
Key learning points
- We know different strategies for addition and subtraction including mental and written strategies.
- Looking at the numbers helps us see which strategy is most efficient.
- Missing number problems can be rearranged to identify an efficient strategy to solve the problem.
Keywords
Subtrahend - The subtrahend is the number to be subtracted. It is the second number in a subtraction.
Efficient - Being efficient means finding a way to solve a problem quickly whilst also maintaining accuracy.
Common misconception
Children may automatically resort to the use of the formal column algorithms. These are not always the most efficient methods.
What do you notice about the numbers? Is there a mental strategy that you could use?
Children need to be encouraged to slow down and look at the numbers in each calculation and to reason about which strategy they would use and to reason about why.
Teacher tip
Licence
This content is © Oak National Academy Limited (2024), licensed on
Open Government Licence version 3.0
except where otherwise stated. See Oak's terms & conditions (Collection 2).Lesson video
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Starter quiz
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6 Questions
Q1.
Use an efficient method to find the sum of 14,875 and 3,123
Q2.
Use an efficient method to find the sum of 9,308 and 5,245
Q3.
Match the expression to the correct difference.
705,000
700,000
720,000
675,000
695,000
Q4.
Use a number line to calculate 50,000 − 34,995 =
Q5.
Use the ‘constant difference’ strategy to calculate 15,000 − 2,375 =
Q6.
Two numbers have a total of 367,200 If one of the numbers is 320,000 what is the other number?
Exit quiz
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6 Questions
Q1.
Match these expressions to the strategy you would use to calculate them.
column addition
partitioning
number line
constant difference then column subtraction
column subtraction
Q2.
A charity needs to raise £200,000 and it has already raised £57,306 Which strategy is most efficient to use to calculate how much more money it needs to raise?
Column addition
Column subtraction
Partitioning
Number line
Q3.
A charity raises £246,803 in a fundraising event. It then raises another £1,907,368 Which strategy is most efficient to use to calculate how much money it has raised in total?
Column subtraction
Partitioning
Number line
Constant difference
Q4.
Find the missing number in this equation.
508,914 = + 205,730
Q5.
Calculate the multi-step equation. Think about the strategy which will be most efficient.
205,677 + 499,998 − 200,000 =
Q6.
Two numbers have a total of 1,690,768 and a difference of 999,412
What are the two numbers? 345,678 and