Tell the students the following story: I want to make Christmas treats to bring into the class for our Christmas party next week. From the survey that you all filled out for me in our last class, I am going to make a chocolate cake and sugar cookies. The cake recipe calls for 1 1/4 cups of sugar and the cookies requires 2 3/4 cups of sugar. I have 3 1/4 cups of sugar at my house. Do I have enough to make the treats for class or do I have to go to the store to get more sugar? If I have to go to the store, how much more sugar do I need?
Give the students some time to work out the problem and have them write their
responses in their mathematics journal. Tell them that we will come back to the
problem later on during the lesson.