Thinkfinity is the Verizon Foundation’s free online professional learning community, providing access to over 60,000 educators and experts in curriculum enhancement, along with thousands of award-winning digital resources for K-12 — aligned to state standards and the common core.
Members of the Verizon Foundation's Thinkfinity online PLC can create and participate in groups to share all sorts of education resources, and there's quite a selection of math education groups to choose from via the search bar! It's free to join!