Question

you give a salesperson $20 for a purchase and recieve change. Use your funcktion to find the amount of change from a $4.50 purchase

Answer 1

It's a purchase and you would receive change of $15.50. 

Keep it simple by counting from 4.50 to 20.00. 

4.50 plus .50 is 5.00, 5.00 plus 15.00 is 20.00.