Starter quiz
- 6 + 4 + 2 =
- 10
- 12 ✓
- 14
- 16
-
- 6 + 6 + 2 =
- '14' ✓
- Match the equation to the sum.
- 9 + 1 + 3⇔13 ✓
- 1 + 9 + 2⇔12 ✓
- 9 + 1 + 4⇔14 ✓
- 9 + 5 + 1⇔15 ✓
- What is the sum of the numbers in the bar model?
- 13
- 15 ✓
- 17
- 19
-
- What addend is missing from the bar model?
- 6 ✓
- 7
- 8
- 9
-
- The missing numbers from this bar model both have the same value. What are both numbers?
- 5 ✓
- 6
- 7
- 10
-
Exit quiz
- How would you find the sum of these calculations? Match them to the strategy you would use.
- 6 + 2 + 4⇔pairs that total 10 ✓
- 5 + 6 + 2⇔near doubles ✓
- 6 + 2 + 6⇔doubles ✓
- What is the sum of the numbers in the bar model?
- 13
- 15
- 17
- 18 ✓
-
- Match up the equations to the correct sum.
- 4 + 4 + 3⇔11 ✓
- 5 + 4 + 5⇔14 ✓
- 6 + 5 + 2⇔13 ✓
- 2 + 4 + 6⇔12 ✓
- What is the missing addend in the bar model?
- 5
- 7 ✓
- 8
- 9
-
- What is 8 + 3 + 8?
- 16
- 17
- 18
- 19 ✓
-
- Which calculations could be used to make this equation correct?
- 4 + 6 + 6 ✓
- 8 + 8 + 2
- 9 + 2 + 6
- 6 + 7 + 3 ✓
-
Worksheet
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Presentation
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Lesson Details
Key learning points
- Using commutativity allows us to simplify a problem with three addends.
- Using known facts allows us to add three addends efficiently.
- Rearranging the addends to identify the pairs that total 10 allows us to add efficiently.
Common misconception
Children rely on one strategy for adding to find a sum and do not consider the values.
Discuss when it is most efficient to use doubles, near doubles, number pairs to 10. Model efficient approaches.
Keywords
Addend - A number added to another.
Commutative - Addition is commutative. This means the order of the addends can be changed without changing the calculation or sum.
Equation - An equation is used to show that one number or calculation is equal to another.
Sum - The total when numbers are added together.
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