During the unit on multiplying fractions, I use this lab to give students a real-life example of how we use multiplying fractions.
I give students this form with a no-bake cookie recipe (will need a microwave) and they are required to convert the recipe to make only one cookie, then convert it to make 8 cookies.
Once I check their math, we discuss how they will actually measure out the ingredients, since there isn't a 4/9 measuring cup. :) The next day we make cookies!
**Updated 11/11/14 - Now includes answer key for groups of 2 and 4**