Subtract by bridging a multiple of ten
I can bridge ten to subtract single digit numbers from two-digit numbers.
Subtract by bridging a multiple of ten
I can bridge ten to subtract single digit numbers from two-digit numbers.
Lesson details
Key learning points
- When we subtract a one-digit from a two-digit number, the equation may be solved more efficiently by 'bridging ten'.
- When bridging a multiple of ten, the number that is subtracted is partitioned to reach the previous multiple of ten.
- Bridging ten is an efficient strategy because number pairs to ten can be used to calculate more easily.
Common misconception
Children may think the multiple of ten before 43 is 30, or partition the subtrahend incorrectly when bridging, meaning they do not use the most efficient strategy.
Display and use the stem sentences to support articulation of how to find the previous multiple of ten. Use ten frames, number lines and one hundred squares to support with appropriate partitioning of numbers.
Keywords
Bridge - A strategy that involves using a multiple of ten as a 'bridge' so numbers can be partitioned to make use of bonds to ten and calculate efficiently.
Partition - To split a whole up into 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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