**Recognise Variable Expressions** *KS3 Revision*

## What you need to know

**Things to remember:**

- The order matters for subtraction and division questions.
- 4-2\neq2-4
- 4\div2\neq2\div4

- When multiplying numbers and variables together, we don’t usually write the multiplication operator.
- The word “over” refers to a fraction.
- 3 over 5\frac{3}{5}

Equations and expressions won’t always be written using maths and operators, but might be written in words, so you need to learn the different names for the operators.

__\times multiplied multiply times product__

__\div divided over divided__

__+ add plus sum__

__– take away minus subtract Difference__

__= is the same as equals__

__() everything__

** **

We now need to learn some slightly more technical language:

**Variable **are quantities that can change, they are usually represented by letters.

**Coefficients **are the numbers that multiply variables.

**Terms **are either numbers by themselves or variables and coefficients.

**Expressions **are mathematical phrases that contain numbers, variables, and operators.

**Equations **tell us when two expressions are equal.

**Coefficients **are the numbers that go before a variable.

**Multiplication**

*Hint: **Remember, when we multiply two variables or a number and a variable we don’t need the multiplication operator.*

*Hint:** Numbers go before variables*

*Hint: **We usually write variables in alphabetical order.*

* *

*Write 5 multiplied by e*

5\times e=5e

Write the product of x and 7

x\times7=7x

Write b multiplies a

b\times a=ab

**Division**

*Hint: **Remember, fractions are just division questions.*

*Hint: **There order of division matters 4\div2\neq2\div4*

* *

*Write z over 2*

\frac{z}{2}

*Write 6 divided by h*

6\div h

* *

**Addition**

*Write the sum of 11 and h*

11 + h

** **

*Write 13 plus g*

13+g

** **

**Subtraction**

*Hint: **There order of subtraction matters 4-2\neq2-4*

* *

** **

*Write the difference of 9 and 6*

9-6

** **

*Write 13 minus g*

13-g

## Example Questions

**Question 1:** Write the product of 6 and g

6\times g=6g

**Question 2:** Write the 17 over k

\frac{17}{k}