As with so many aspects of mathematical enquiry, there is little that is "original", or "brand new", but that does not diminish the outcome of work that borrows from "those who have gone before". In this piece the author "borrows" from the work of Desargues, Monge, Ceva, Menelaus, van Aubel, and Gergonne. This novel approach to providing a proof…

Mathematical proof is a strange concept; it is ironical that there is no precise definition of what constitutes a mathematical proof since without definitions there can be no proof--Dreyfus, 1999. Proof can be divided into many different categories. In this article, the author discusses these categories. She looks first at the background of proof…

"Proofs and refutations: the logic of mathematical discovery" by Imre Lakatos was published posthumously in 1976. This is a fascinating, if somewhat hard to access, book which calls into question many of the assumptions that people make about proof--one may start reading with a clear sense of what mathematical proof is, but almost certainly will…

The author states her belief that mathematics is a human construct based on axiomatic systems, and that these constructs are both personal and social. She argues that to succeed in mathematics, learners' personal constructs need to be aligned with formal globally agreed mathematical conventions. Put more simply, she informs her students that…

The author conducted a workshop with colleagues in which awareness of Pythagoras' theorem was raised. This workshop was an unforgettable event in the author's life because it was the first time that she had interacted with teachers from a different school system, and it allowed her to develop presentation skills and confidence in her own…

There is much to be learned and pondered by reading "Proofs and Refutations," by Imre Lakatos. It highlights the importance of mathematical definitions, and how definitions evolve to capture the essence of the object they are defining. It also provides an exhilarating encounter with the ups and downs of the mathematical reasoning process, where…

Every year the Institute of Mathematics Pedagogy meet for a residential conference in July working together to focus on particular aspects of teaching and learning mathematics. The conference is open to all, and includes all sorts of people involved in mathematics and education. This year the focus was on proof and narrative. This article looks at…

One of the great pleasures of being a mathematics teacher lies in experiencing that very special buzz in the classroom that occurs when every single student is thoroughly engrossed in the task the teacher has set them. The teacher knows that in those precious moments genuine learning is taking place, however noisy and chaotic it may appear to an…

In mathematics, the generation and validation of new knowledge frequently involves alternating between two major activities: (1) making generalizations; and (2) developing arguments. Engaging students in reasoning-and-proving is a challenging goal, but also an important one for deep learning and sense making in mathematics. In this article, the…

Many high-school mathematics teachers have likely been asked by a student, "Why does the cross-multiplication algorithm work?" It is a commonly used algorithm when dealing with proportion problems, conversion of units, or fractional linear equations. For most teachers, the explanation usually involves the idea of finding a common denominator--one…

A proof's potential to promote understanding and conviction is one of the main reasons for which proof is so important for students' learning of mathematics. Unless students realise the limitations of empirical arguments as methods for validating mathematical generalisations, they are unlikely to appreciate the importance of proof in mathematics.…

People are inclined to desire proof of theories if they have developed a certain philosophical style when they are quite young. It is a style that questions the authority for things, so that they can hold fast to what is good. Regarding mathematical proof, this author argues that it is only those who are prepared to take their own authority for…

This article was written as a result of the author reading "MT177," a special issue dedicated to the teaching of "proof" in mathematics. He used the ideas in this special issue for planning his session "mathematical reasoning and proof," which was part of a weekend course for primary trainees. It consisted of three activities: (1) How many…

This article "opens up" the study of the relationship between quadrilaterals and circles to two sets of quadrilaterals--those that can be drawn either inside (cyclic) or outside (tangential) a circle (or both). Of course, "all" triangles are both cyclic and tangential. Or, to use the traditional Euclidean language for triangles, a unique…