teaching--the goal toward which we all should strive.

It is a safe maxim never to tell a child what one can lead him by
questioning to see for himself. To illustrate: Suppose an elementary
arithmetic class already know thoroughly how to find the area of a
rectangle by multiplying its base by its altitude, and that we are now
ready to teach them how to find the area of a triangle. Let us see
whether we can lead them to "develop" the rule instead of learning it
out of the text; that is, we will proceed inductively. First draw a
rectangle 4 by 6 on the board.

Q. What do we call this figure?

A. A rectangle.

Q. How shall we find its area?

A. Multiply its base 4 by its altitude 6; the area is 24.

Q. Now I draw a line diagonally across the rectangle; how
many figures are there?

A. Two. (Teacher here gives new word "triangle" and explains
it.)

Q. How do the base and altitude of the triangles compare
with the base and altitude of the rectangle?

A. They are the same.