From PARCC (Partnership for Assessment and Readiness for College and Careers), a consortium of 23 states involved in developing Common Core tests:
Sample Mathematics Item: Grade 5 “Two Aquarium Tanks”:
PARCC's rationale for this assignment in terms of Common Core Standards:
1. Discuss the ratio of mathematical challenge to nonmathematical challenge in solving these two problems.
2. Discuss the ratio of the effort involved in coming up with problems like these to the effort involved in justifying them--i.e., explaining how effective they are in meeting the Common Core standards (from "Evidence Statement" all the way down to "Scoring Information").