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New
Year 2
Calculate the difference in different contexts
I can calculate the difference in different contexts.
New
New
Year 2
Calculate the difference in different contexts
I can calculate the difference in different contexts.
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Lesson details
Key learning points
- You calculate the difference by counting on from the known part to the whole.
- The difference is the answer to a subtraction calculation.
- The difference is one of the parts that make the whole.
Keywords
Difference - The amount which a number is greater or smaller.
Subtraction - To partition one part from another (the subtrahend from the difference), or to decrease an amount by taking an amount away.
Count on - A mental strategy used to add numbers.
Common misconception
Children think that 'counting on' is used solely as a strategy in addition.
Children should be made aware that the strategy for 'counting on' can be used in addition but is used as a strategy for subtraction in this lesson where we are finding the difference between two numbers close in value.
Children should be encouraged to only use 'counting on' as a strategy for finding the difference when it is an efficient choice (when the numbers being compared are close in value).
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.
Which equation has been written to find the difference between 9 and 6?
9 + 6 = ?
6 - 9 =?
Q2.
9 and 6 have a difference of
Q3.
Here, we are finding the difference between…
2 and 5
7 and 2
Q4.
How many have we ‘counted on’ on the number line?
Q5.
Which pairs of numbers have the same difference of 5?
10 and 4
7 and 3
Q6.
If I know the difference between 10 and 6 is 4, working backwards, I also know the difference between ___ and ___ is 4
7 and 4
5 and 3
Exit quiz
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6 Questions
Q1.
When would we be best to use the ‘counting on’ strategy to find the difference?
When the numbers are far apart.
If we cannot work out the answer.
Q2.
If a book costs £4 and a toy car costs £12, how would we efficiently calculate the difference in price?
Count on from £4 to £12
Add £4 and £12
Q3.
A teddy costs £9 and a toy car costs £12, how would we calculate the difference in price?
Subtract £9 from £12
Add £9 and £12
Q4.
It takes Sofia 4 minutes to walk to school.
It takes Jun 12 minutes to walk to school.
How much longer does it take Jun to walk to school than Sofia? minutes.
Q5.
Jacob wants to buy a new pencil case that costs £12 and he has saved £9 so far.
How much more money does Jacob need to save? £
Q6.
When playing a game, the difference between Izzy’s score and Lucas’ score is 3, Izzy scored 9 so how many points could Lucas have scored?
Additional material
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