This Instructional Activity is a part of the Lesson 3, Unit 8, Grade 8. In this activity, students have a chance to look for some more rational numbers that are close to Square Root of 2. The idea is that they will look, for a while, for a fraction that can be multiplied by itself where the product is exactly 2. Of course, they won't find one, because there is no such number. In the whole-class discussion that follows, irrational number is defined. For this activity, it is best if students do not have access to a calculator with a square root button.