Substituting Variables

Which of these could be a variable?

•  $3$  

• w

• 9

• 1,027

Evaluate the expression

 $x\div2$  if x=4

Evaluate the expression  $z+5$  if z = 9

Evaluate the expression  $7b$  if b= 5. 

Note: when a number is next to the variable, it means multiply.

Evaluate the expression  $12-c$  if c= 11. 

Evaluate the expression  $a+b$  , if a=3 and b=9

Evaluate the expression  $9m$  if m=2 

Note: when a number is next to the variable, it means multiply.