Common Core State Standard: 8.EE.3 

Grade  8 
Subject  MATH 
Domain  Expressions & Equations 
Theme  Work with radicals and integer exponents 
Standard  Use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities, and to express how many times as much one is than the other. For example, estimate the population of the United States as 3 
Reference URL  http://www.corestandards.org/Math/Content/8/EE 