n - 9

n + 9

n/9

9n

a/a

a+a

1+a

10 - s 

s + 10

s - 10

s/10

6 + g

6g

g - 6

Something that changes

An unknown value

An equation

A numeric expression

12 - r

12/r

12 + r

12r

5w

5 + w

4x4x4x4x4

4x5

5x5x5x5

14 - b

14/b

14 + b 

b - 14 

5m

8m

5 x m

40

8 x m

x − 4

4 − x

4 + x

4x

30 + w

30w

7 + w

7w

3 x p

2p

2 + p

2 - p

product of 3 and ‘y’

sum of 3 and y

difference between 3 and y

3 divided by y