New
New
Year 3

Use known facts to add and subtract multiples of 100 within 1000

I can add and subtract multiples of 100

New
New
Year 3

Use known facts to add and subtract multiples of 100 within 1000

I can add and subtract multiples of 100

Lesson details

Key learning points

  1. Known facts can be used to help calculate with multiples of a hundred.
  2. If we know that 2 ones plus 4 ones equals 6 ones we know that 2 100s plus 4 100s equals 6 100s.
  3. Number facts to 10 can help us to add and subtract multiples of a hundred.

Common misconception

Pupils may find it difficult to connect calculating with hundreds with known facts.

Pupils need to be encouraged to 'unitise' hundreds to make calculation easier, seeing 500 as 5 lots of one hundred.

Keywords

  • Known facts - A known fact is something that you already know and can use to help you.

  • Multiple - A multiple is the result of multiplying a number by another whole number.

Pupils may need base ten blocks ('hundreds') to support their thinking and help them connect calculating with hundreds with known facts (e.g. 3 + 4 = 7 so 300 + 400 = 700). Number lines and bar models are also useful representations for pupils.
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.
What is 40 + 40?
8
16
44
Correct answer: 80
Q2.
100 − 40 =
Correct Answer: 60, sixty
Q3.
What is the sum of 30, 30 and 10?
60
Correct answer: 70
80
90
Q4.
What is the value of the missing part in the bar model?
An image in a quiz
Correct Answer: 20, twenty
Q5.
What is the missing number? + 10 = 120
Correct Answer: 110, one hundred and ten
Q6.
Which pair of numbers do not add up to equal 90?
30 + 60
40 + 50
70 + 20
Correct answer: 90 + 10

6 Questions

Q1.
Which of these numbers are multiples of a hundred?
Correct answer: 300
Correct answer: 500
650
Correct answer: 900
Q2.
Which known fact could you use to help you calculate 500 + 300?
5 + 2 = 7
Correct answer: 3 + 5 = 8
3 + 2 = 5
3 + 3 = 6
Q3.
What is 100 less than 600?
Correct Answer: 500, five hundred
Q4.
Which pairs of numbers are equal to 600?
Correct answer: 200 and 400
Correct answer: 300 and 300
500 and 200
Q5.
What is the value of the missing part in the bar model?
An image in a quiz
Correct Answer: 100, hundred, one hundred
Q6.
Which pairs of numbers could be used to complete the bar model?
An image in a quiz
100 and 700
Correct answer: 200 and 500
Correct answer: 300 and 400
Correct answer: 600 and 100