Add and subtract mentally without bridging a boundary
I can add and subtract mentally without bridging a boundary with one or more digits changing
Add and subtract mentally without bridging a boundary
I can add and subtract mentally without bridging a boundary with one or more digits changing
Lesson details
Key learning points
- Known facts to 10 can be applied when adding and subtracting 100s, 1,000s, 10,000s and 100,000s
- When adding and subtracting mentally, the language of unitising supports us in addition to using known facts.
- An understanding of the structure of numbers and place value supports when we add and subtract mentally.
Common misconception
Children may believe that only one digit will change when adding two numbers where one addend has only one non-zero digit.
This is usually correct but what would happen if the digit changed to a value of 10 or greater? Then we would need to regroup (another lesson).
Keywords
Addend - An addend is a number added to another. They are also known as the parts.
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).
Video
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Starter quiz
6 Questions
Exit quiz
6 Questions
6,451,038
4,651,038
4,471,038
4,453,038
4,451,238
8,265,792
8,265,292
8,265,272
8,265,268