CCLS - Math: 8.NS.1

Category
The Number System
Sub-Category
Know That There Are Numbers That Are Not Rational, And Approximate Them By Rational Numbers.
State Standard:
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.