This PowerPoint is designed to make students think about addition and subtraction. In the slides students will determine which answer to the equation does not belong. Students will need to examine all four spaces and figure out which three of the four boxes have the same answer. There are 10 slides.
You can do this whole group, in small groups, or with partners. I use white boards and groups of 4. I allow students to work independently for the first minute and then allow them to work together to come up with their answer.