I like to teach cost per unit when we are dividing with decimals because I think it is the most practical real-life application.
* A brief Powerpoint with 4 examples of calculating cost per unit (can be edited)
* An activity to discover the cheapest way to eat pizza (making it at home, buying a frozen one, or buying one from the store) involving lots of cost per unit calculations! I did this whole-class.
* A worksheet with 3 problems for students to decide the best deal between different size/brands/prices of boxes of cereal, juice boxes, and ice cream bars
* A review with 12 word problems in which students solve decimal division problems, and have to explain their reasoning in complete sentences. This can be edited to use your own students' names! They love that.