New
New
Year 2

Use efficient strategies to solve problems

I can use efficient strategies to solve addition and subtraction problems.

New
New
Year 2

Use efficient strategies to solve problems

I can use efficient strategies to solve addition and subtraction problems.

Lesson details

Key learning points

  1. Known facts can be used to help us solve equations and problems efficiently.
  2. Numbers can be partitioned to bridge ten to help us work efficiently.
  3. When equations are solved, it is important to choose a strategy that allows you to solve the problem efficiently.

Common misconception

When faced with problems, children may revert to using inefficient counting strategies instead of more efficient calculation strategies.

Record equation required to solve a problem, then explicitly discuss the most efficient strategy to solve it, drawing on prior knowledge and strategies such as use of known facts and the bridge ten strategy.

Keywords

  • Strategy - A method used to solve a problem or equation.

  • Data - Another word for information.

  • Bar chart - A graphical display of data using bars of different heights; another name for a bar graphs.

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).

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6 Questions

Q1.
67 can be partitioned in different ways. Match the multiple of 10 with another number that sums to 67
Correct Answer:60,7

7

Correct Answer:50,17

17

Correct Answer:40,27

27

Correct Answer:30,37

37

Correct Answer:20,47

47

Q2.
Which equation will come next in the pattern?
An image in a quiz
48 = 28 + 20
Correct answer: 48 = 10 + 38
48 = 0 + 48
Q3.
Which of these equations show that 92 has been correctly partitioned into three parts?
92 = 50 + 30 + 2
Correct answer: 92 = 40 + 2 + 50
92 = 10 + 10 + 9
Correct answer: 92 = 2 + 20 + 70
Q4.
Which of these equations show that 55 has been correctly partitioned into three parts?
Correct answer: 55 = 50 + 5 + 0
Correct answer: 55 = 50 + 4 + 1
55 = 5 + 50 + 2
55 = 3 + 2 + 40
Q5.
What is the missing addend in this equation? 74 = 40 + + 30
Correct Answer: 4
Q6.
What is the missing addend in this equation? 38 = + 30 + 2
Correct Answer: 6

6 Questions

Q1.
Alex’s sunflower is 5 cm shorter than Sam’s. What strategy can Alex use to find how tall his sunflower is?
An image in a quiz
Correct answer: Subtract 5 ones from 67 cm
Subtract 5 tens from 62 cm
Subtract by bridging a multiple of 10
Q2.
There were 43 woodlice under a log. 8 woodlice crawled out. How many woodlice are left under the log? Which equation represents this problem?
Correct answer: 43 − 8 = ___
43 + 8 = ___
43 + ___ = 8
Q3.
I had 39 seeds in the packet and I put in 30 more. How many seeds do I have altogether? seeds
Correct Answer: 69
Q4.
Look at the data in the table. There is a difference of 10 between two of the groups of birds. Which two groups of birds have a difference of 10?
An image in a quiz
Blackbird
Correct answer: Robin
Correct answer: Magpie
Pigeon
Q5.
Sam saw 5 more blackbirds to add to the total. How many blackbirds did Year Two see altogether?
An image in a quiz
Correct Answer: 53
Q6.
Year Three saw 6 fewer pigeons than Year Two. How many pigeons did Year Three see?
An image in a quiz
Correct Answer: 57