New
New
Year 5

Solve comparison and change problems in a range of contexts

I can solve comparison and change problems in a range of contexts.

New
New
Year 5

Solve comparison and change problems in a range of contexts

I can solve comparison and change problems in a range of contexts.

Lesson details

Key learning points

  1. Change can be described using multiplication or division. Division can be represented as multiplication by a fraction.
  2. The sentence 'The __________ is ___ times the size of the __________' supports us to describe a comparison or change.
  3. If units are different, we should convert so that they are the same - this supports us to calculate.
  4. To find a missing factor, we can divide the product by the known factor.

Common misconception

Manipulating equations can result in errors.

To find a missing factor, we can use known facts where applicable, or we can divide the product by the known factor. Always encourage children to describe each part of the equation and what it represents.

Keywords

  • Bar model - A bar model is a pictorial representation of a problem where bars are used to represent the known and unknown quantities.

  • Multiplicative - A multiplicative relationship is a comparison between numbers that relates to multiplication (and hence division). In a multiplicative relationship, the parts are equal.

  • Times the __________ - Times the __________ is a phrase that is used to compare measures multiplicatively. For example, one tree might be 'three times the height' of another tree - it is three times as tall.

It is important that children are fluent with their times table facts so they can focus on the scaling structure without overload. Always offer practical examples where possible.
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.
Izzy has a football that has a mass of 540 g and a tennis ball. The football is nine times the mass of the tennis ball. What is the mass of the tennis ball?
9 g
90 g
Correct answer: 60 g
531 g
Q2.
A full kettle contains 1 l 400 ml of water and a full cup contains 200 ml of water. You can fill cups with water from the full kettle.
Correct answer: 7 cups
70 cups
0.7 cups
700 cups
Q3.
A flight to France takes one fifth of the time it takes to fly to New York. If it takes 1 hour 30 minutes to fly to France, how long does it take to fly to New York?
6 hours
5 hours 30 minutes
7 hours
Correct answer: 7 hours 30 minutes
Q4.
What is 8 times the value of £2.50? 8 times the value of £2.50 is .
Correct Answer: £20, 20 pounds, 20 Pounds
Q5.
Alex is saving for a new laptop. He has saved £70 and has saved $${1}\over{4}$$ of the cost of the laptop. Which expressions shows how much does the laptop costs?
£70 × $${1}\over{4}$$
£70 × 3
Correct answer: £70 × 4
£70 × 5
Q6.
Alex is saving for a new laptop. He has saved £70 and has saved $${1}\over{4}$$ of the cost of the laptop. How much more money does he need to save? Alex needs to save £ .
Correct Answer: 210, £210

6 Questions

Q1.
20, 000 people watched Arsenal play and 80. 000 watched Manchester City play. How many times more people went to Manchester City?
8 times as many.
6 times as many.
Correct answer: 4 times as many.
2 times as many.
Q2.
There are 25 g of blueberries in a small box and 800 g in a large box. How many times the small box is the large box?
4
16
24
Correct answer: 32
Q3.
There are 900 g of strawberries in a large box and 90 g in a small box. Which word completes this sentence? The small box is one the mass of the large box.
Correct Answer: tenth, Tenth
Q4.
Which equations can be formed from the bar model?
An image in a quiz
Correct answer: 60, 000 × ? = 20, 000
Correct answer: 20, 000 × ? = 60, 000
Correct answer: 60, 000 ÷ ? = 20, 000
Correct answer: 60, 000 ÷ 20, 000 = ?
Q5.
What is the value of the ? in the equations? 60, 000 ÷ ? = 20, 000 and 60, 000 ÷ 20, 000 = ?
30, 000
3, 000
300
30
Correct answer: 3
Q6.
What is the value of the ? in this equation 60, 000 × ? = 20, 000
3
30
300
Correct answer: $${1}\over{3}$$