An unknown is a quantity that has a set value but is represented by a symbol or letter.

A variable is quantity that can take on a range of values.

A formula is a rule linking sets of physical variables in context. The plural of formula is formulae.

Representing an unknown or variable

Maths

In this unit, pupils formalise algebraic notation and terms and begin to formulate an understanding of basic algebraic manipulation. This understanding is built upon in the future unit where pupils learn how to solve linear equations

In this unit, pupils learnt how to represent the structure of a problem with two unknowns using a diagram. This understanding is built upon in this unit and formalised

Expressions and equations

A letter can be used to represent {{}}, (quantities with set values) or variables (quantities that can take on a range of values). 

$$n$$ represents the number of hours Andeep sleeps

Andeep says: I sleep 8 hours a night, I can write the number of hours I sleep for any number of nights as $$8n$$. which of the following are true?

True - multiplying any number by 3 makes the value bigger

False - Multiplying a negative number by 3 makes the value smaller

True or false: $$3n$$ is always bigger than $$n$$

To cook a lamb ‘well done’ the recipe says the length of time (mins) is 50 × mass (kg) + 20. What is the variable in this scenario?

For the statement $$x+y=44$$. What value can $$x$$ have if it is 10 times bigger than $$y$$?

is smaller than $$x$$ when $$x$$ is between 0 and 1 

is smaller than $$x$$ when $$x$$ is negative

is smaller than $$x$$ when $$x$$ is less than 10

Match the expression with its relationship to the size of $$x$$

The value halfway between 13 and 27 is {{ }}

Complete the calculation: $$20+40\times 4$$ = {{ }}

False - an equation must have an equals sign

True or false: $$52y$$ is an equation for the number of weeks in a given number of years.

Sofia is thinking of a number. When she adds 6 then multiplies her number by 4 she gets 40. Which is an equation representing Sofia's number?

Which of the expressions below represent the algebra tiles in this diagram?

This lesson will soon be taken down.

Representing an unknown or variable

Lesson outcome