Differentiating Math Instruction in a Corrections setting

The online course: Differentiated Instruction: Math concluded last week. We had many participants from various educational settings: classrooms, online, one on one and corrections. During our discussions we shared various strategies for differentiating math into the classroom. In particular, our corrections people have an added challenge of presenting math using manipulatives when many such items are restricted. What have you tried in your classroom for differentiating math and in particular, what ideas would you have for our corrections teachers?