I love to use this PowerPoint on my new Smart Board! It allows students (or teacher) to add real numbers to a blank and building Venn diagram. The last slide is a blank Venn diagram that students may use as guided notes when following along. The concepts covered are NATUARAL NUMBERS, WHOLE NUMBERS, INTEGERS, RATIONAL NUMBERS, and IRRATIONAL NUMBERS. I like to add a little discussion on non-real numbers when I use this with advanced students. The activity can be changed or expanded in many ways, and I provide a few suggestions in the presentation. ENJOY!