Add two-digit numbers without crossing the tens boundary
I can add two-digit numbers without crossing the tens boundary.
Add two-digit numbers without crossing the tens boundary
I can add two-digit numbers without crossing the tens boundary.
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Lesson details
Key learning points
- Two-digit numbers can be added by using Base 10 equipment to combine the tens and the ones.
- Partitioning two-digit numbers can help when adding them.
- Either the tens or the ones can be added first, the sum will remain the same.
- Considering the number of tens when adding two-digit numbers can help estimate the sum.
Keywords
Partition - To split a whole up into parts.
Common misconception
Children may transpose digits in the numbers, so add tens as ones and vice versa. They may also use inefficient counting strategies to count on in tens, then ones.
Ensure that the numbers are partitioned into tens and ones, so their place value is clear and the link to known facts can be easily seen. Refer back to known facts using the stem sentence 'I know that..., so I know that ...'
To help you plan your year 2 maths lesson on: Add two-digit numbers without crossing the tens boundary, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 2 maths lesson on: Add two-digit numbers without crossing the tens boundary, 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.
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Explore more key stage 1 maths lessons from the Addition and subtraction of two 2-digit numbers unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Lesson video
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Starter quiz
6 Questions
3 + 1 + 50 + 20
2 + 30 + 4 + 20
2 + 40 + 50 + 4
Exit quiz
6 Questions
4 + 3 + 30 + 20
30 + 2 + 20 + 3
3 + 30 + 40 + 2