Why is math difficult to differentiate?

Personally, I believe that math is a more difficult subject for teachers to differentiate than reading and writing. I don't think it's because it can't be done, but rather because it simply hasn't been done. My hunch here is that the traditional structures for teaching math (i.e. model the procedure, practice the procedure together, send students off to practice independently) don't lend themselves well to differentiation. Common practices for teaching literacy, though,--guided reading groups and the writing workshop model--do allow children to pursue work at a variety of levels.

What would it take to find structures that work for differentiating math? The guided reading and writing workshop models have been adapted so widely because the basic structures that underlie these programs are clear. If teachers had easy to use structures for differentiating math instruction, I really believe that they would be happily adopted.

Current math curriculum materials don't even yet recognize the reality of students' differing needs. All the curriculum guides that I have been expected to use as a teacher are designed for straight-graded classrooms and essentially assume that all students are working at the same level. Even programs which are less lock-step and offer more open-ended lesson plans, are usually designed for use with straight grade-level groupings. Adapting them for use in a multi-age classroom is incredibly challenging. Although there are lessons in most curricular programs that work for a range of learners, and sometimes guides come with sidebars explaining adaptations and extensions, most often it is up to the teacher to figure out a way to make the differentiation actually work in the classroom. Our district's new program came with extra reproducibles for struggling and advanced students, but shuffling between all of these extra books is a lot of extra work. It seems to me that math curriculum packages should be produced with the assumption that students in every classroom represent a wide range of skills and abilities and that lessons should be designed with predictable structures that make doing differentiation easy.