This article explores how a focus on understanding divisibility rules can be used to help deepen students' understanding of multiplication and division with whole numbers. It is based on research with seven Year 7-8 teachers who were observed teaching a group of students a rule for divisibility by nine. As part of the lesson, students were shown a…

Proportional reasoning is an important cornerstone in children's mathematical development. This sort of reasoning has been shown to develop across the early years of schooling (ages 8 to 10) through the middle years (ages 11-14). In the early years, children tend to use additive reasoning to generate solutions to problems, while later comparisons…

The activities suggested in this article are intended for use with lower secondary school students. The "Australian Curriculum: Mathematics" states that students in lower secondary school should "investigate the relationship between features of circles such as circumference, area, radius and diameter" and "use formulas to solve problems involving…

There is an old saying that "there is more than one way to skin a cat." Such is the case with finding the height of tall objects, a task that people have been approximating for centuries. Following an article in the "Australian Primary Mathematics Classroom" (APMC) with methods appropriate for primary students (Brown, Watson, Wright, & Skalicky,…

In August 2010, ACER held its annual conference in Melbourne. The theme of the 2010 conference--"Teaching Mathematics? Make It Count"--was chosen to highlight that mathematics education is an area of high priority in Australia. In the author's own presentation to the conference, he outlined research into an area that he believes is very important…

The introduction of negative numbers should mean that mathematics can be twice as much fun, but unfortunately they are a source of confusion for many students. Difficulties occur in moving from intuitive understandings to formal mathematical representations of operations with negative and positive integers. This paper describes a series of…

In this article, the authors discuss how acknowledging and embracing that the sample space is one of many ways to partition the set of all possible outcomes impacts the teaching and learning of sample space and probability. After recounting an exchange surrounding two viable answers to a probability question, the authors detail how developments…

Archimedes, the famous Greek mathematician, lived from 287 BCE until approximately 212 BCE. He thought that the figure of two semi-circles on a straight line enclosed by a larger semi-circle resembled a shoemaker's knife. Archimedes called this figure an "arbelos" since arbelos is the Greek word for a shoemaker's knife. The author describes the…

This paper reports on the experiences of a group of teachers engaged in an action research project to develop critical numeracy classrooms. The teachers initially explored how contexts in the media could be used as bases for activities to encourage student discernment and critical thinking about the appropriate use of the underlying mathematical…

Contemporary debates on effective pedagogies for K-12 mathematics have called for shifts in the way teachers and teacher educators conceptualise mathematics as a subject and how it should be taught. This is reflected by changes in the curriculum including the inclusion of a strand called Working Mathematically within K-12 mathematics curriculum…

The focus of this paper is the use of National Assessment Program in Literacy and Numeracy (NAPLAN) items to develop students' competence in reading mathematical text, to promote thinking strategies including estimation, and to evaluate alternative solutions for errors and misconceptions. Showing students test items and discussing strategies for…

This article is the second in a series of two papers which suggest some practical, spreadsheet-based ideas for helping students to make appropriate connections between particular algebraic concepts. Solving equations has traditionally been taught as a pen-and-paper process. Spreadsheets, such as that of Excel, provide a contemporary, and powerful…

Spatial reasoning is a skill that needs to be developed in students as it is important in geometry for determining total surface areas and volumes of 3-dimensional shapes (Liedtke, 1995). Simply teaching children the formulae, in this case for finding total surface areas, can limit them in understanding mathematics conceptually (Bonotto, 2003).…

This article illustrates spatial thinking tasks through cube diagrams and drawings. The author talks about the pentacube diagram that is based on the principle that a vertical cube-edge is shown "vertically". The author describes how to extend isometric drawing to include triangular wedges that are made by slicing single cubes, bi-cubes,…

These days, multiplying two numbers together is a breeze. One just enters the two numbers into one's calculator, press a button, and there is the answer! It never used to be this easy. Generations of students struggled with tables of logarithms, and thought it was a miracle when the slide rule first appeared. In this article, the author discusses…