New
New
Year 6

Explain how to represent an equation with a bar model

I can explain how to represent an equation with a bar model.

New
New
Year 6

Explain how to represent an equation with a bar model

I can explain how to represent an equation with a bar model.

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Lesson details

Key learning points

  1. The model can represent a scaling structure with one part being __ times the size of the other.
  2. The model can represent an additive structure.

Keywords

  • Represent - To represent something means to show something in a different way.

Common misconception

Pupils opt to represent the problem using two separate bar models that are stacked on top of one another.

Whilst pupils can represent the maths how they wish, these problems tend to be more efficiently represented using a singular bar model with the whole at the top. Further iterations of these bar models can then be represented underneath.

Where one of the unknowns is the the sum of the other unknown and an additional part (difference contexts), encourage pupils to draw a separate bar model to represent this so they can see how the original bar model can be altered accordingly so that the unknowns are of the same form.
Teacher tip

Equipment

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).

Lesson video

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6 Questions

Q1.
8 × f − 6 × g can also be written as:
8 × f − 6 × g
Correct answer: 8f − 6g
6g − 8f
f8 − g6
Q2.
What is the value of the gap marked ? in the bar model? Give your answer in pounds. £
An image in a quiz
Correct Answer: 40, 40 pounds, £40
Q3.
What is the value of the gap marked b in the bar model? Give your answer in pounds. £
An image in a quiz
Correct Answer: 30, 30 pounds , £30
Q4.
What is the value of the gap marked ? in the bar model? Give your answer in pounds. £
An image in a quiz
Correct Answer: 240, 240 pounds, £240
Q5.
What is the value of d in the bar model? Give your answer in pounds. £
An image in a quiz
Correct Answer: 62, 62 pounds, £62
Q6.
This pattern is made up of two different-sized squares. What is the length of the longer sided square marked l? cm
An image in a quiz
Correct Answer: 40

6 Questions

Q1.
A bag of soil weighs 3 kg less than a bag of pebbles. If a represents the bag of soil and b represents the pebbles, tick the equation that matches to context.
Correct answer: b − a = 3 kg
a − b = 3 kg
3 kg − b = a
3 kg − a = b
Q2.
A chocolate bar costs 50 p more than a lolly. 2 chocolate bars and 2 lollies cost £2.20 Which pair of equations show this?
2a + 2b = £2.20; a + b = 50 p
Correct answer: 2c + 2l = £2.20; c − l = 50 p
Correct answer: 2a + 2b = £2.20; a − b = 50 p
Q3.
A toy car is 1.5 cm longer than a toy motorbike. 3 toy cars and 2 motorbikes have a total length of 29.5 cm. What is the length of the toy car and motorbike? Tick the appropriate pair of equations.
2a + 2b = 29.5 cm; a − b = 1.5 cm
Correct answer: 3a + 2b = 29.5 cm; a − b = 1.5 cm
2a + 3b = 29.5 cm; a − b = 1.5 cm
2a + 3b = 29.5 cm; b − a = 1.5 cm
Q4.
Solve the following problem. A toy car is 1.5 cm longer than a toy motorbike. 3 toy cars and 2 motorbikes have a total length of 29.5 cm What is the length of a toy motorbike? cm
Correct Answer: 5, 5 cm
Q5.
Solve the following problem. A toy car is 1.5 cm longer than a toy motorbike. 3 toy cars and 2 motorbikes have a total length of 29.5 cm What is the length of a toy car? cm
Correct Answer: 6.5, 6.5 cm
Q6.
A chocolate bar costs 50 p more than a lolly. 2 chocolate bars and 2 lollies cost £2.20 What is the cost of one chocolate bar? What is the cost of one lolly?
Correct answer: Chocolate bar = 80 p; Lolly = 30 p
Chocolate bar = £1; Lolly = 50 p
Chocolate bar = 90 p; Lolly = 40 p
Chocolate bar = 30 p; Lolly = 80 p
Chocolate bar = 85 p; Lolly = 35 p