Starter quiz
- Solve the equation in the most efficient way. 48 + 34 = ______
- '82' ✓
- Which of the following is correct?
- 27 + 35 = 52
- 62 + 29 = 81
- 28 + 15 = 43 ✓
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Find the missing whole in the bar model. The missing whole is ______- '92' ✓
Which equation is represented by this number line?- 10 + 3 + 4 = 17
- 57 + 17 = 74 ✓
- 57 + 13 = 70
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Which of the following is the missing addend? ______ + 36 = 51- 87
- 15 ✓
- 25
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- Find the missing addend. 47+ ______ = 73
- '26' ✓
Exit quiz
- Solve the addition problem. Izzy has 34 beads on her bracelet and she adds 42 more. Use the strategy you find most efficient to solve the problem. ______
- '76' ✓
- Which strategy is the most efficient when solving this problem? There are 38 cows in the field and 57 in the barn. How many cows are there altogether?
- Partition one addend ✓
- Partition both addends
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- Which of the following is the most efficient way to solve this problem? There were 68 children in the hall, then 23 more children went in. How many children are in the hall now?
- Izzy sees 42 birds and Andeep sees 76 birds. How many more birds does Andeep see? How many tens will be in the missing addend when the equation is written for this problem?
- 2 tens
- 3 tens ✓
- 4 tens
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- Izzy had 46 seeds in her packet and Andeep had 72 seeds in his packet. How many more seeds did Andeep have than Izzy?
- 26 ✓
- 25
- 6
-
- Andeep counts 59 minibeasts and Izzy counts 83 minibeasts. How many more minibeasts does Andeep count?
- 24 ✓
- 34
- 44
-
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- Partitioning the addends can help us to solve problems involving two-digit numbers.
- Once we have written the equation, we must think carefully about the most efficient strategy to use.
- It is important to be able to calculate mentally before adding two 2-digit numbers.
Common misconception
When the amount of processing required for a task increases, children often default to inefficient strategies such as counting in ones if the use of efficient strategies are not yet automatic.
When solving problems, continue to focus upon, and discuss, the most efficient strategies to use to ensure that this thinking becomes automatic.
Keywords
Partition - To split a whole up into parts.
Efficient - Not wasting time or effort. An efficient strategy is one we can carry out easily.
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