This article explains the generation of Kaprekar's constant in terms that upper elementary pupils can understand. The procedure is explained and the result proven. This is an example of a new, interesting problem for students that gives them drill in subtraction at the same time. (LS)

An outline of the way that fractions might be presented in ninth grade algebra is given, and implications for elementary school instruction are noted. (DT)

Using negative digits in writing numerals and in calculation is explained. This is the second article in the series; for the first, see Vol. 1, No. 7, Nov., 1972, pp. 8-9. (DT)

A six-step method of teaching subtraction by renaming is presented, using money as the learning vehicle. (MP)

Using various aspects of mathematical structure as unifying concepts is stressed. Specific examples are given based on the concept of equivalent fractions and on the addition property of equality. (LS)

A distinction is made between an algorithm and the justification for the algorithm. Examples of both are given for the operations with whole numbers. (DT)

A subtraction algorithm for numbers having several digits is described. The algorithm requires that, for digits in the same place, the smaller is always subtracted from the larger. (SD)

The major portion of the article establishes the basis for the stated rule - to divide by a fraction, turn it upside down and multiply. With this background, three justifications for the rule are given. Several possible errors in students' use of the rule are noted. (LS)