New
New

Use knowledge of doubling, halving and the 2 times table to solve problems

I can use knowledge of doubling, halving and the 2 times table to solve problems.

New
New

Use knowledge of doubling, halving and the 2 times table to solve problems

I can use knowledge of doubling, halving and the 2 times table to solve problems.

Lesson details

Key learning points

  1. Doubling is a multiplication where one of the factors is 2
  2. When one of the factors is 2, the other factor is half of the product.
  3. Doubles facts to 5 can help to double and halve 2-digit numbers.

Common misconception

Children may revert to inefficient strategies to solve problems e.g. counting on, using fingers.

Within the second learning cycle, children are encouraged to evaluate strategies used by others. The most efficient strategies should be discussed together throughout the first learning cycle to support with this.

Keywords

  • Double / Doubling - To become twice as many / to multiply by two.

  • Half / Halving - One of two equal parts of a whole / To divide into two equal parts.

  • Check - To evaluate working, ensuring our response provides an answer to the given problem.

For Task A, children can team up to create their own problems for their friends, or teachers can choose to create their own problems in advance. For Task B, group or paired work would be preferable. It is worth noting that it is only doubles of whole numbers that are even.
Teacher tip

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.
Match the statements to find half of each number.
Correct Answer:Half of 12 is equal to ,6

6

Correct Answer:Half of 20 is equal to,10

10

Correct Answer:Half of 14 is equal to,7

7

Correct Answer:Half of 40 is equal to,20

20

Q2.
What number goes in both sentences to make them correct?
An image in a quiz
Correct Answer: 24
Q3.
Which of these problems could I use halving to find the missing factor?
___ × 5 = 20
Correct answer: 2 × ___ = 16
___ × 10 = 40
Q4.
What is the missing factor in this equation? 2 × = 16
Correct Answer: 8
Q5.
Find the missing factor is this equation. × 2 = 26
Correct Answer: 13
Q6.
There are 18 socks in a drawer. How many pairs of socks can be made? pairs
Correct Answer: 9

6 Questions

Q1.
Match to complete each sentence.
Correct Answer:Double 12 is equal to,24

24

Correct Answer:Double 30 is equal to,60

60

Correct Answer:Double 9 is equal to,18

18

Correct Answer:Double 15 is equal to,30

30

Q2.
There are 13 biscuits in a packet. How many biscuits will be in two packets? biscuits
Correct Answer: 26
Q3.
Match the statements.
Correct Answer:Double 14 is equal to 28,Half of 28 is equal to 14

Half of 28 is equal to 14

Correct Answer:Double 7 is equal to 14,Half of 14 is equal to 7

Half of 14 is equal to 7

Correct Answer:Double 13 is equal to 26,Half of 26 is equal to 13

Half of 26 is equal to 13

Correct Answer:Double 40 is equal to 80,Half of 80 is equal to 40

Half of 80 is equal to 40

Q4.
Find the missing factor in each equation.
Correct Answer:2 × ___ = 18 ,9

9

Correct Answer:___ × 2 = 40,20

20

Correct Answer:2 × ___ = 22 ,11

11

Correct Answer:___ × 2 = 26 ,13

13

Q5.
Which of these numbers are examples of a double of a whole number?
25
Correct answer: 18
Correct answer: 16
21
Correct answer: 50
Q6.
If there are 28 pencils in two packets, how many pencils are in one packet? pencils.
Correct Answer: 14

Lesson appears in

UnitMaths / Multiplying by 2, doubling and halving (factors and products)