The Arithmetic of Computers is the first volume in the British edition of a series entitled TutorTexts. The books employ techniques developed in the U.S.A. during research in automatic teaching methods. Each is essentially an elementary introduction to its subject, little or no previous knowledge being assumed. The volumes to be published in this country will include a selection of those published in the U.S.A., together with works by British authors employing the same techniques.
A TutorText is not read like an ordinary book. Although the pages are numbered in the usual way, they are not read consecutively. This is because the presentation resembles a conversation between teacher and student. Information is offered in small units and the reader's understanding is then tested by means of multiple-choice questions. His response determines what page he turns to next. An incorrect answer leads to a page containing more discussion of the information just imparted; a correct answer leads to a new unit of information and on to the next question. Thus, until a question is answered correctly, the reader cannot proceed to new information; his rate of progress is determined by his ability to give the correct answers. Best results are likely to be obtained with this book through several short learning sessions rather than with a few long ones.
The choice of The Arithmetic of Computers as the first volume in the British TutorText series is no random one. High-speed computing machines are having an increasing impact upon our lives. It is, therefore, important that as much as possible shall be done both to dispel the atmosphere of magic and mystification which has tended to develop around them, and to enable their basic principles to be generally understood. The present book does not attempt to deal with more than one aspect of computers: it is designed to give an understanding of two of the number systems used in these machines. Such understanding requires only a little elementary arithmetic and an open mind.
The idea of "number systems" other than the familiar decimal system may seem strange at first. But our conventional way of counting in tens is neither the only nor the simplest way. After working through this TutorText, however, the reader will have a sound knowledge of the history of the binary and octal number systems, the two most commonly used in computer arithmetic.
This book is the result of a co-operative effort by a team of American writers led by Norman A. Crowder, whose researches led to the development of the TutorText technique. In agreement with Mr. Crowder, some modifications have been made to the American text in the preparation of this edition, and I have added several tables and a few footnotes.
Richard Goodman
Brighton College of Technology