Try this box:

THE RULE:  Square it!
                           (You figure out the outputs.)

input: 4  ->  rule: ( )^2  ->  output: __  ...  input: -3  ->  rule: ( )^2  ->  output: __  ...  (be careful!)
 

input: 0  ->  rule: ( )^2  ->   output: __  ...  input: square root of 7  ->  rule: ( )^2  ->  output: __
 

What's the domain? ________________

What's the range? ________________