A method for converting francs to dollars and dollars to francs is shown to involve the harmonic mean. (MP)

Addition, multiplication, and exponentiation form the beginning of a natural hierarchy of binary operations on the positive integers. By employing operations above exponentiation in this hierarchy, it is possible to obtain large numbers as an immediate result of combining small familiar numbers. (Author/MP)

The use of the hundred chart is discussed as an effective means of teaching the concepts of least common multiple and greatest common factor. (MP)

A series of carefully planned activities is described for introducing first-grade students to place value with two-digit numerals. (JT)

A group of 31 institutionalized retarded adolescents responded to 18 conservation of number tasks. (Author)

This study investigated whether 4- and 5-year-old children can evoke and use kinetic imagery and whether the ability to use kinetic imagery depends on the attainment of concrete operations. Results yielded no evidence of association between kinetic imagery and conservation. (Author/JMB)

When adults judge which of two digits is numerically larger, their response times decrease linearly with the numerical difference. For fourth- and seventh-grade children, the slope of the function relating judgment time to numerical difference is similar to that of adults, but much steeper for kindergarten and first-grade children. (Author/JMB)

Establishes two categories of numbers: (1) relatively frequent numbers and (2) relatively infrequent numbers. The numbers in the first group are manipulated by people and depend, at least to some degree, on memorization; those in the second group are essentially machine inputs. Examples of the first group are examined. (SED)

Extracts from "Experimenting with Numbers" by Margaret Stern demonstrate the use of Stern Blocks to develop the conceptual base on which learning disabled students can build further mathematical skills. (DB)

Plastic Easter eggs are useful devices for teaching basic mathematics skills, from counting activities to graphing. Eggs are used to reinforce addition, subtraction, and multiplication skills; column addition, estimation, statistics, and other topics are introduced. Sample activities are described. (JL)

Four experiments were conducted to study explanations of why children make relative number judgments inconsistent with their counting. Results are discussed in relation to judgments children make when they use matching, and in light of Klahr and Wallace's (1973) account of number development. (PCB)

Case studies describe the positive responses of two elementary learning disabled students involved in an experimental number fact program. The program emphasized development of strategies matched to individual learning needs in a nontraditional approach to the organization of addition facts. (Author/CL)

A general method and a variant for divisibility are presented, with specific examples. (MNS)

Some lesson ideas with magic squares are given. The parametric form of three-by-three and four-by-four squares are each discussed and a worksheet is included on doing and making magic squares. (MNS)

Fifteen trainable mentally retarded students (four-six years old) were generally capable of rule-governed and other counting skills, and some could mentally compare numbers and choose the larger. Some Ss demonstrated a basic form of problem solving: they used the addition identity and commutativity principles to shortcut computational effort.…