According to Maccini & Gagnon, manipulatives make math more accessible for special needs students (2002). The use of manipulatives can help these students get a better understanding a mathematical concept or procedure that is being taught.
This way they do not need to rely on their memory of formulas to figure out a problem because formulas are easy to forget.
Manipulatives are a great way to get students active in the lesson and make your lessons more engaging for the student. Manipulatives also help make abstract ideas into a more real concept.
Some different manipulatives that may be helpful are fraction strips, which students can make on their own, base -10 blocks, counters, which could be coins, beads, etc., geo-boards, and unifix cubes.