Mary Harbolt knows how to manage student manipulatives. She teaches a 4th/5th blend at Faubion Elementary in Portland, Oregon, and wrote in with this fabulous idea...
I have a marble system in my classroom. [Students work together to earn--and sometimes lose--marbles that can earn them special privileges and/or rewards.]
If a math manipulative hits the floor and I pick it up, it's my marble. If a student picks it up first, no marble is lost. This system makes the students hypervigilant. At the end, if all manipulatives are put away, they get a marble.
Thank you, Mary, for an idea that may keep other teachers from "losing their marbles"...or perhaps, their base ten linear pieces! Have another idea for managing manipulatives? We'd love to hear from you!