The perimeter is the distance around a 2D shape.

An expression contains one or more values, where each value is separated by an operator.

Area is the measurement of a flat surface. It measures 2D space.

Explain how to balance equations with addition or subtraction expressions

Maths

In this unit pupils will explain how to balance equations with addition or subtraction expressions and use their knowledge of balancing equations to solve problems. In the future 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 prior unit pupils explained how increasing or decreasing the minuend affected the difference. They used known facts to explain how adjusting the minuend made mental calculation easier. In this unit pupils will explain how to balance equations with addition or subtraction expressions and use their knowledge of balancing equations to solve problems.

Calculating using knowledge of equivalence in addition and subtraction

True or false. Lawn A and lawn B have the same perimeter.

Which expressions can be used to represent the perimeter of this lawn?

What is the missing dimension labelled x for this pair of lawns? {{ }} m

Lawn A and lawn B have the same area. What is the missing dimension labelled x on lawn B? {{ }} m

A is made up of lawn and pond. What is the area of the lawn? {{ }} $$m^2$$

The area of the whole garden is 99 $$m^2$$ and the area of the lawn is 78 $$m^2$$    What is the missing dimension of the pond labelled x? {{ }} m

Which of the following expressions has the same sum as 41.6 + 7? Can you reason without calculating?

What is the area of this rectangle? {{ }} $$cm^2$$

What is the area of this rectangle? Check the measurements carefully. {{ }} $$cm^2$$

What is the perimeter of this rectangle? {{ }} cm

Use an efficient strategy to calculate 132.7 + 489.92 = {{ }}

Complete the equation that is represented by the bar model. 1,267 + c = {{ }}

This lesson will soon be taken down.

Explain how to balance equations with addition or subtraction expressions

Lesson outcome