To represent something means to show something in a different way.

Explain how to represent an equation with a bar model

Maths

Compare the structure of problems with one or two unknowns

Represent the structure of a problem with two unknowns in context

Explain why there is sometimes only one solution to a problem

Represent and solve problems with two unknowns efficiently

Use a bar model to represent spatial problems with two unknowns

Solve problems with two unknowns in a range of contexts

Explain how you know you have found all the possible solutions to a problem with two unknowns

Explain how to balance an equation with two unknowns

Solve problems with two unknowns with one, several and infinite solutions

In this unit pupils will compare and represent the structure of problems with two unknowns using a bar model. They will systematically solve problems with two unknowns using trial and improvement. In the future unit this understanding is formalised through the use of algebraic notation. 

In the prior unit pupils explained how to balance equations with addition or subtraction expressions and used knowledge of balancing equations to solve problems. In this unit pupils will compare and represent the structure of problems with two unknowns using a bar model. They will systematically solve problems with two unknowns using trial and improvement.

In this unit pupils will compare and represent the structure of problems with two unknowns using a bar model. They will systematically solve problems with two unknowns using trial and improvement.

Solving problems with two unknowns

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.

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?

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.

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


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

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?

8 × f − 6 × g can also be written as:

What is the value of the gap marked ? in the bar model? Give your answer in pounds. £{{ }}

What is the value of the gap marked b in the bar model? Give your answer in pounds. £{{ }}

What is the value of d in the bar model? Give your answer in pounds. £{{ }}

This pattern is made up of two different-sized squares. What is the length of the longer sided square marked l? {{ }} cm

Explain how to represent an equation with a bar model

Lesson outcome