Virtual Manipulatives-Third-Graders Learn About Fractions Using Virtual Manipulatives: A Classroom Study conducted by Kelly Reimer and Patricia Moyer, offers information on the effects that virtual manipulatives have on students mathematical understanding. Thier study showed an increase in comprehension of fractions after using virtual manipulatives.  (Reimer & Moyer-Packenham, 2005)

Using Manipulatives to Teach Elementary Mathematics-Researches at Mississippi State University conducted a study “Using manipulatives to teach elementary mathematics” and noted that “It is important for children to have a variety of materials to manipulate and the opportunity to sort, classify, weigh, stack and explore if they are to construct mathematical knowledge” (Boggan, Harper, & Whitmire, 2001)