This PowerPoint which includes 2 retro Sesame Street videos is a great review of the Real Number System and all its subsets. Students are to look at a group of numbers and decide which doesn't fit. Then the students explain how the number is different. At the end, the students are asked to give their own examples. My students loved this partly because I interjected a few slides with funny pictures to determine the "Not like the Others", and with the videos, you cannot go wrong! This PowerPoint covers rationals, irrationals, integers, whole numbers, and natural numbers with a little humor in a non-threatening approach. I like to have the students respond on individual white boards as we go along or this could be used as a math center. Enjoy!