Monsters are used as an example to illustrate that multiplication of the natural numbers is associative. (JT)

Early experience with grouping objects is valuable for later understanding of and work with place value, division, and multiplication. Examples are drawn from the Developing Mathematical Processes Curriculum Project at the Wisconsin Research and Development Center for Cognitive Learning. (RS)

A method of multiplying using fingers is described and an explanation given. The method is then generalized to other number bases. (MP)

A method is discussed for justifying to students the fact that the product of two negative integers is positive. (DT)

In the winter of 1965, an experimental course in Elementary Number Theory was presented to a 6th grade class in the Hosmer School, Watertown, Massachusetts. Prior to the introduction of the present material, students had been exposed in class to such topics from the University of Illinois Arithmetic Project as lattices, number lines, frame…

Greatest common factor and least common multiple are the concepts used to play this game that has football as its basis. Rules and examples are given. (MP)

A systematic search is given for products where reversing the digits does not change the answer. Related questions are suggested that can be solved by the same discovery approach. (MP)