In high school solid geometry, in order to study the positional relationship of geometry in space by algebraic means, an arbitrary point O and a unit orthogonal base {i, J, k} are selected to establish a spatial rectangular coordinate system. In this sense, (1)i, j and k are three paired vertical unit (modulo 1) vectors in the spatial rectangular coordinate system. (3) Their function is to represent space vectors (or vectors). Usually, I, J and K are called a cardinal number. Because vectors can be translated in space, there is this basis. Any vector in space can be represented by a vector whose starting point is at the origin. If the components of the space vector starting from the origin on the three-dimensional coordinate axis are 3, 2, 1 respectively. Then this vector can be expressed as 3i+2j+k. This vector can also be expressed as (3,2, 1).