Investigations in Number, Data, and Space is a complete K-5 mathematics curriculum designed to help elementary school children understand the fundamental ideas of number and operations, geometry, data, measurement and early algebra. It was developed in the 1990s at TERC, an education research and development organization in Cambridge, Massachusetts, and is now widely used. Research has shown that students taught with the Investigtions curriculum do at least as well as other students in solving straight calculation problems, and they do better when it comes to understanding number relationships, word problems, and more complex calculations.

A second edition of Investigations is now available through publisher Scott, Foresman.  The new edition is aimed at developing “computational fluency” in the base ten number system, which means explaining the meaning of its operations and their relationships.  For example, kindergarten and grade one students solve subtraction problems by physically removing paper blocks from a pile.  During grades two and three they learn subtraction “facts” and solve different types of problems, such as comparisons and missing parts.  in grades three and four, Investigations students learn important generalizations about subtraction, and they compare strategies for subtracting.

The Investigations web site includes useful information on math teaching strategies, as well as a schedule of workshops for teachers using the curriculum.