# Common Core MATH 8 NS 1 Grade 8 The Number System Know That There Are Numbers That Are Not Rational And Approximate Them By Rational Numbers

**The Number System: Know That There Are Numbers That Are Not Rational, And Approximate Them By Rational Numbers.**

Know that numbers that are not rational are called irrational. Understand informally that every number has a decimal expansion; for rational numbers show that the decimal expansion repeats eventually, and convert a decimal expansion which repeats eventually into a rational number.