Web Gem: Opus

A great new resource for math teachers, Opus is a free math problem bank.  Search by Common Core standards and topics, or browse the Core directly. The questions are heavier on grades 7 and 8, but site promises that more is coming for grade 6.  There is material for grades 4-5, but the decision to fully support those grades has not yet been made.

A free login is required create an assignment sheet and answer key, both of which can be exported to a Word 2010 or Google document.