Delta-K Volume 41 Issue 2

Journal of the Mathematics Council of the Alberta Teachers’ Association

Volume 41 Issue 2, June 2004

This is my first issue of delta-K since I took over as editor from Klaus Puhlmann in the fall of 2003. I want to thank the many people who have been so supportive during this transition, including AT A staff advisor Dave Jeary, ATA publications supervisor Karen Virag, MCATA publications director Shauna Boyce and all the executive members of the Mathematics Council of the Alberta Teachers’ Association (MCATA). Your encouragement and support have meant a great deal!

Of course, I also want to express my thanks, appreciation and congratulations to Klaus Puhlmann as he retires as editor after so many years of superior and dedicated service. We all owe Klaus this sincere acknowledgement of his outstanding work. Thank you, Klaus!

At our last meeting, the MCATA executive voted to begin the process of making delta-K a refereed journal.

This move will bring delta-K (and, by extension, MCATA) increased recognition for its publishing efforts while maintaining its traditional high standards and further enhancing its reputation. This move will change guideline 8 in the guidelines for manuscripts on the inside front cover. Once delta-K becomes a refereed journal, articles will be submitted for an initial overview to the editor, who will in tum send the articles to two reviewers, each of whom has a special interest in mathematics education. Based on the reviewers’ recommendations, articles will appear in future issues of delta-K. The final decision to publish any article remains with the editor. Guidelines for this process are not yet finalized but will become available in upcoming months.

delta-K remains committed to encouraging and publishing high-quality articles pertaining to the professional development of mathematics educators, and articles that stimulate thinking and explore new ideas and viewpoints. We continue to be interested in articles with a classroom or scholarly focus. Please feel free to submit your ideas regarding mathematics instruction-in the form of articles, activities, letters or problems. Our goal is to help teachers and other educators share their ideas and strategies with the aim of continually supporting and refining mathematics instruction across the province.

I have selected some of my favourite problems for the last page of this issue. If you have a problem you want to share, send it to me at locwen@uleth.ca. I’ll try to include it in the next issue. Enjoy!

A. Craig Loewen

Front Matter

EDITORIAL

A. Craig Loewen

From the President’s Pen

Len Bonifacio

4 – 9

Determining the Angles Between Two Lines

David E. Dobbs

10 – 12

Sums of Arithmetic Sequences: Several Problems and a Manipulative

A. Craig Loewen