Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions (e.g., π2). *For example, by truncating the decimal expansion of *√*2, show that *√*2 is between 1 and 2, then between 1.4 and 1.5, and explain how to continue on to get better approximations.*

**8.NS The Number System**

**8.NS.A** *Know that there are numbers that are not rational, and approximate them by rational numbers.*