8.NS.A.2: 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.
Students will learn how to approximate square roots by drawing dots, as seen here. Then students will learn how to bound a square root by making tables, as seen here. Students should also be asked to make rough approximations of square roots by guessing, as seen here.