## Friday, February 19, 2016

### Review of "Take A Look At A Good Book," by Steven Kahan ISBN 0895031426

Review of

Take A Look At A Good Book, by Steven Kahan ISBN 0895031426

Professor Kahan was the editor of the alphametics column in Journal of Recreational Mathematics for many years and for the last eight I was co-editor of the journal. He always carried out his editorial duties very well and occasionally contributed a problem or a paper.
An alphametic is an arithmetic problem, most often addition, but the other arithmetic operations can be used as well. Each of the digits is replaced by a letter in a one-to-one manner and the goal is to have a problem where the letters make words and the words state a coherent message. Solving the problem requires only a knowledge of the rules of arithmetic, some applied logic and a bit of persistence. Computers can also be used to solve them and in the last years of the publication of Journal of Recreational Mathematics I noted a significant increase in the size of some of the alphametics that were published in the column.
The content of the book can be split into three categories, the first one is a set of number fact fillers. For example, on page 41 there is the factoid:
“Every integer of the form ABABAB is divisible by 7 and every integer of the form ABCABC is divisible by 11.”
The second category is composed of the text that sets the context for some of the alphametics. There is some history, a significant aspect of puzzles and some that are just made up silliness. The third category are alphametics presented for solution with no preamble or lead-in.
Solutions to all of the problems/puzzles are included at the end and they are presented in two forms. The first is in the form of an extended hint as to how to tackle the problem and the second is a complete solution.
Alphametics are a problem that can be solved by all people, from children in elementary school to adults. They are challenging as well as entertaining, especially when the message is a good one. For a long time Kahan has been the best there is at creating quality alphametics and this book is an existence proof of that fact.