Problem Solving and Extended Response (sources of problems for extended response and short-answer)
TIPS - Tipping the Scales In Problem Solving. Open-response items for early elementary through junior high. Student work included. From a grant project at W.I.U.
Balanced Assessment in Mathematics – Contains a library of 300 assessment tasks for grades K to 12. (Originally from the Harvard Graduate School of Education.)
Problems With A Point – Problems “with a Point” help students in grades 6-12 learn new mathematical ideas by building on old ones. In a searchable database format.