High Quality Content by WIKIPEDIA articles! Investigations in Number, Data, and Space is a K-5 mathematics curriculum, developed at TERC in Cambridge, Massachusetts, USA. The curriculum is often referred to as Investigations or simply TERC. Patterned after the NCTM standards for mathematics, it is among the most widely used of the new reform mathematics curricula. Instead of reading textbooks and solving long pages of out-of-context mathematical problems, students are guided through constructivist activities and work to develop their own understanding of mathematics. The curriculum underwent a major revision in 2005 - 2007.