Starter quiz
- What is the missing part on the bar model?
- 120
- 100
- 20 ✓
-
- What is the missing whole on the bar model?
- 132
- 130
- 150 ✓
- 120
-
- Use this bar model. Which addition calculations are correct?
- 9 tens = 19 tens + 10 tens
- 9 tens + 10 tens = 19 tens ✓
- 19 tens = 10 tens + 9 tens ✓
- 9 tens + 19 tens = 10 tens
-
- 170 = 40 + 100 + ______. What is the missing part?
- '30' ✓
- Sofia buys some ribbon that is 170 cm long. She gives 70 cm to her friend. How much does she have left ? ______ cm.
- '100 ' ✓
- Which calculations could represent this bar model?
- 140 = 40 + 100 ✓
- 100 - 140 = 40
- 100 + 40 = 140 ✓
- 100 = 140 - 40 ✓
- 100 - 40 = 140
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Exit quiz
- What are the addends in this calculation 90 + 30 = 120 ?
- 30 and 120
- 90 and 30 ✓
- 90 and 120
-
- If I know 6 + 5 = 11 what is 6 tens + 5 tens? ______
- '11 tens' ✓
- Match the tens to the multiples of ten.
- 3 tens + 9 tens⇔30 + 90 ✓
- 4 tens + 8 tens⇔40 + 80 ✓
- 5 tens + 7 tens⇔50 + 70 ✓
- 6 tens + 6 tens⇔60 + 60 ✓
- 7 tens + 4 tens⇔70 + 40 ✓
- When adding 80 to 60, how can the addend 60 be partitioned to bridge 100?
- 10 + 50
- 20 + 40 ✓
- 30 + 30
-
- Which addition is equivalent to 80 + 20 + 50?
- 80 + 50
- 80 + 70 ✓
- 20 + 50
- 80 + 20
-
- A number has been partitioned into something and 40 to bridge 100. What is the missing addend? 70 + ______ + 50 = 150
- '30' ✓
Worksheet
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Presentation
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Lesson Details
Key learning points
- The language of unitising helps us to use number facts to 20 to add multiples of 10 crossing the hundreds.
- Crossing the tens boundary helps us to cross the 100s boundary if we think in tens.
- Partitioning an addend helps us to cross the 100 boundary when adding.
Common misconception
Lack of fluency with number facts to 20 can hinder progress in applying them to multiples of ten.
Ensure that fluency with number facts to 20 is secure or supported so that pupils can apply them.
Keywords
Addend - An addend means any of the numbers that are added together.
Bridging 100 - Bridging 100 means partitioning one addend to make a number bond to 100 then adding the remaining part.
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