Clearly grasping the object for consideration.
This is an important aspect of the idea of sets. For instance,
when one counts objects, it is not enough to simply count. It
is important to first achieve a solid grasp of the scope of objects
to be counted. Also, when grasping a concept such as the
isosceles triangle, it is important to determine and clearly indi-
cate the scope of objects under consideration (just one printed
triangle, a number of triangles created with sticks, or any tri-
angles one can think of with the presented triangles simply
offered as examples).