New
New
Year 2

Halve even 2-digit numbers and multiples of 10

I can halve even 2-digit numbers from 12 to 28 and unitise and apply known facts to halve even multiples of 10

New
New
Year 2

Halve even 2-digit numbers and multiples of 10

I can halve even 2-digit numbers from 12 to 28 and unitise and apply known facts to halve even multiples of 10

Lesson details

Key learning points

  1. Halving facts to 10 can help to halve 2-digit numbers.
  2. To halve 2-digit numbers, partition the 2-digit number, halve the tens and the ones, then recombine.

Common misconception

Incorrectly partitioning and halving odd multiples of 10

Ensure children use representations where they are able to see the partitioning of the number into an even multiple of 10 and 10 more. That way, they can clearly see they are still finding half of 30 for example.

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.

  • Partition - The act of splitting an object or value down into smaller parts.

Support children to apply known halving facts to halve even 2-digit numbers. Using unitising, children can halve multiples of 10 and ones digits to find one half of a range of 2-digit numbers where there is no regrouping.
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.
Use the bar model to complete the sentence. Half of 6 is equal to
An image in a quiz
Correct Answer: 3, three
Q2.
If I know that half of 8 is equal to 4, then I know that _____________
Correct answer: double 4 is equal to 8
double 3 is equal to 6
double 2 is equal to 4
Q3.
Which facts are represented by this bar model?
An image in a quiz
Double 3 is equal to 6
Correct answer: Double 5 is equal to 10
Half of 8 is equal to 4
Correct answer: Half of 10 is equal to 5
Q4.
Which equation is represented by this bar model?
An image in a quiz
2 × 3 = 6
Correct answer: 2 × 4 = 8
2 × 5 = 10
Q5.
Alex had 10 marbles. He gave half to Jacob. How many marbles did Jacob get? marbles
Correct Answer: 5, five
Q6.
Aisha gave half of her biscuits to Alex. Aisha was left with 7 biscuits. How many biscuits did Aisha have to begin with? biscuits
Correct Answer: 14

6 Questions

Q1.
Match the statements.
Correct Answer:Double 3 is equal to 6,Half of 6 is equal to 3

Half of 6 is equal to 3

Correct Answer:Double 5 is equal to 10,Half of 10 is equal to 5

Half of 10 is equal to 5

Correct Answer:Double 6 is equal to 12,Half of 12 is equal to 6

Half of 12 is equal to 6

Correct Answer:Double 4 is equal to 8,Half of 8 is equal to 4

Half of 8 is equal to 4

Q2.
Which facts will help you to find half of 14 by partitioning the parts?
An image in a quiz
Correct answer: Half of 10 is equal to 5
Half of 8 is equal to 4
Half of 6 is equal to 3
Correct answer: Half of 4 is equal to 2
Q3.
Match the known facts.
Correct Answer:Half of 4 tens is 2 tens,Half of 40 is equal to 20

Half of 40 is equal to 20

Correct Answer:Half of 2 tens is 1 ten,Half of 20 is equal to 10

Half of 20 is equal to 10

Correct Answer:Half of 6 tens is 3 tens,Half of 60 is equal to 30

Half of 60 is equal to 30

Correct Answer:Half of 8 tens is 4 tens,Half of 80 is equal to 40

Half of 80 is equal to 40

Q4.
How can you find half of 28?
Correct answer: Find half of 2 tens and half of 8 ones
Find half of 8 tens and half of 4 ones
Correct answer: Find half of 20 and half of 8
Find half of 80 and half of 4
Q5.
Look at the image of Base 10 blocks. What is half of 24?
An image in a quiz
Correct Answer: 12
Q6.
Find half of 50 by partitioning. Half of 50 =
Correct Answer: 25

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