This Instructional Activity is a part of the Lesson 3, Unit 7, Grade 8. The properties of equality have been proven for rational numbers, which are central in school mathematics. As we begin to solve equations that require roots, we are confronted with the fact that we may be working with irrational numbers, which have not yet been defined for students. Therefore, we make the assumption that all of the properties of equality for rational numbers are also true for irrational numbers(i.e., the real numbers, as far as computations are concerned). This is sometimes called the fundamental assumption of school mathematics (FASM).