A general model for two-level multivariate data, with responses possibly missing at random, is described. The model combines regressions on fixed explanatory variables with structured residual covariance matrices. The likelihood function is reduced to a form enabling computational methods for estimating the model to be devised. (Author)

Describes a system for using the World Wide Web to distribute computational tasks to multiple hosts on the Web that is written in Java programming language. Describes the programs written to carry out the load distribution, the structure of a "distriblet" class, and experiences in using this system. (Author/LRW)

Examines elementary students' perspectives on the engagement potential of particular mathematical problems and students' views on classroom problem-solving activities in general. Nonroutine examples that focused on important reasoning processes and did not involve computation had the greatest engagement potential, whereas computational problems…

Studies 6- to 8-year olds' responses to sliced task, standard and choices were discontinuous quantities, and non-sliced task, standard was continuous and choices were discontinuous quantities in order to discover whether children use half boundary in ratio comparisons between continuous and discontinuous quantities. Reveals that "dhalf" plays a…

Interviews 53 sixth grade students individually in an attempt to discover whether wrong interpretations of the algebraic structure found in an algebraic context occurs in a purely numerical context. Concludes that students' difficulties with the algebraic structure were also found in purely numerical contexts. (Contains 27 references.) (Author/ASK)

Presents a problem introducing pupils to the ideas of consecutive and integer while practicing addition. Investigates the overall pattern of results with regard to formulating some general results, considers the algebra of the problem, and suggests proofs of why some numbers can and others cannot be formulated in this way. (ASK)

Assesses the status and use of the hand-held calculator in the current school curriculum. Comments on current proposals to restrict its use in the examination room at A-level. Concludes that at the stage of A-level mathematics, calculations that are not practicable without calculating aids cannot be avoided without indefensible contrivance.…

Presents solutions for a problem concerning doubling a recipe from a previous article on number concepts in the October 1997 issue. (ASK)

Reacts to an article published in a previous issue of this journal on the effects of graphing calculators and computer algebra systems (CAS) on students' manual calculation and algebraic manipulation skills. Considers the contribution made by Jean-Baptiste Lagrange to thinking about the role of CAS in teaching algebra. (ASK)

Nigerian second graders (n=58) were given instruction on using counting and thinking strategies. Compared to 54 controls, they performed better on recall and retention of number facts. (SK)

Presents worksheets for students to practice substituting whole numbers into fairly simple symbolic expressions. (MKR)

Describes a strategy to make chi-square calculations and interpretations more understandable by presenting the theory behind the test to the students in a visual manner. Involves using dihybrid corn to generate a large sample of chi-squares followed by plotting a frequency distribution to get at the meaning behind the chi-square table. (JRH)

Debates the place of standard methods, the calculator, and mental mathematics in elementary education. Proposes a framework for computation that emphasizes a sequence for introducing computational procedures. (ASK)

Giving children time and encouragement to explain methods of calculation is a useful strategy. Uses this strategy with a group of children and discovers surprising thinking by one child on number facts. (ASK)

Discusses childrens books about money dealing with the recognition of coins, bills, and their value; counting and calculating; minting and printing; meaning of words, symbols, and pictures on money; history; and money from around the world. Describes activities and provides a bibliography. (PEN)