Mathematical Reasoning Activity: Odd One Out Money

In order to use Odd One Money, I put my students in groups of three or four and gave them half of the printable below.  They needed to discuss which amount of coins they would leave out of the group of four and justify their answers.  They listed the shape they left out and their reasons why on a sheet of notebook paper. 
Multiple answers are correct and I often require a minimum number of responses from the group.

Artistry of Education