Benchmark 12B
Habits of Mind: Computation and Estimation
Grades 6-8, page 291

Decide what degree of precision is adequate and round off the result of calculator operations to enough significant figures to reasonably reflect those of the inputs.

NSES Content Standard A  
Science as Inquiry: Abilities necessary to do scientific inquiry 
Grades 5-8, page 148 
Use mathematics in all aspects of scientific inquiry. Mathematics is essential to asking and answering questions about the natural world. Mathematics can be used to ask questions, to gather, organize and present data, and to structure convincing explanations.