New
New
Year 1
Use knowledge of addition facts within 10 to add within 20
I can use knowledge of addition facts within 10 to add within 20
New
New
Year 1
Use knowledge of addition facts within 10 to add within 20
I can use knowledge of addition facts within 10 to add within 20
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Lesson details
Key learning points
- Addition facts within ten can be applied to addition within 20, e.g. if 3 + 2 is equal to 5 then 13 + 2 is equal to 15
- A number line can be used to show the link between addition of one-digit numbers and teen numbers
Keywords
Addition - Bringing two or more numbers or things together to make a new total.
Add - Bringing two or more numbers or things together to make a new total.
Plus - A synonym for add, represented by the symbol +
Common misconception
Children may rely on counting strategies instead of using known facts to add larger numbers.
Make comparisons between addition within 10 and within 20, looking for patterns. Make sure children notice that the ones digit stays the same when we add numbers with the same ones digits such as 3 + 2 and 13 + 2.
Use number lines to show addition within 10 and within 20, drawing out the similarities. Make sure children notice that the ones digit stays the same when we add numbers with the same ones digits.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), 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.
What is the missing part?
Q2.
What is the sum of the parts in this picture?
Q3.
Which equation represents this part-part-whole model?
8 = 1 + 9
9 + 1 = 8
Q4.
I have 7 pencils altogether. 3 are red and 4 are yellow. Which equations would represent this?
3 + 7 = 4
3 = 7 + 4
Q5.
What does the 2 represent in this equation? 2 + 8 = 10
The whole group.
The counters we can see.
Q6.
Use the number patterns in the equations to find the missing addend in the last equation.
4 + 0 = 4
3 + 1 = 4
2 + 2 = 4
1 + = 4
Exit quiz
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6 Questions
Q1.
Which of these part-part-whole models match the story?
First Izzy ate 11 strawberries and then she ate 5 more. How many strawberries has she eaten?
Q2.
Which equation below helps you to find the answer to 13 + 6 = ___?
10 + 6 = 16
10 + 3 = 13
Q3.
Complete the sentence: 1 plus 7 is equal to 8, so 11 plus 7 is equal to
Q4.
Complete the sentence: 6 plus 3 is equal to 9, so 16 plus 3 is equal to
Q5.
First, Izzy collected 12 stones and then she found 6 more. How many stones does she have now? stones
Q6.
First, Andeep had 11 stickers and then Izzy gave him 5 more. How many stickers does Andeep have now? stickers
16
sixteen