"... common business procedures with which every one should be familiar... ."

From the Preface to Junior Business Training by Frederick G. Nichols (American Book Company, New York, 1923) a text book for "boys and girls in junior high schools." The book has two parts, the first aimed at every one, "regardless of his vocational aim."

Page 16: Cash Account.

The task, as illustrated above, was to keep a detailed record of your family's household spending for one month. [Chick to enlarge. $3.50 on the telephone bill!]

What a crappy old idea! Familiarizing kids-- in junior high, no less!-- with how to manage money! What good is that going to do them in the real world? Good grief. Fortunately we as a society are well over that  crappy old notion. We now know what kids in junior high really need to learn to become productive members of society.

In Grade 8, instructional time should focus on three critical areas: (1) formulating and reasoning about expressions and equations, including modeling an association in bivariate data with a linear equation, and solving linear equations and systems of linear equations; (2) grasping the concept of a function and using functions to describe quantitative relationships; (3) analyzing two- and three-dimensional space and figures using distance, angle, similarity, and congruence, and understanding and applying the Pythagorean Theorem.

 I don't know about you, but I use bivariate linear equations every day. 

         ∑ xy
r =  ----------
               2     2
      √ ∑x   ∑y

See? I just used one! Pearson's correlation coefficient.

[Just to be clear, note that in the denominator, it's the square root of the sum of all x's squared times the sum of all y's squared. That was the best square root symbol I could find.]