You travel to your favorite vacation spot, and when you get there you buy a postcard to send to your classmates. There’s a machine at the post office that sells stamps, but only takes pennies, nickels and dimes. How many different ways can you find to pay for the postcard stamp that costs 27¢?
Challenge 1: How much change would you get if you went to the counter and bought two 27¢ stamps with $1?
Challenge 2: How much change would you get if you bought three 27¢ stamps with $1?