There is a new kind of calculator being manufactured. It's an EduCALC, a teaching calculator with two display units. It has the usual small, red numerical readout facing you as you operate it, and also it has another BIG display unit showing the same number in the opposite direction toward your audience or class. Its big, bright neon digits have that same twinkling fascination for the viewer that has attracted him to his own calculator.

Anyone who has tried to communicate numbers and calculations to other people knows the problem. The display digits are just too little to be read if you hold the calculator up to be seen, even before a small audience. Yet reading off the numbers loses attention and interest, and so does writing them on a blackboard. The EduCALC gives us a way to really hold an audience, a way to give our calculations "sex appeal."

This important new visual aid for teaching is in use at the University of California, for example. They have found that it captures the attention of students all the way to the rear of a large, well-lit lecture theater.

The "Master" Calculator: Each EduCALC has its own built-in calculator. These calculators are made by Hewlett-Packard. Three different EduCALC models are available:

Model		Master
21 GD		HP-21 Scientific Calculator
22 GD		HP-22 Business Management Calculator
25 GD		HP-25 Programmable Scientific Calculator

The "Slave" Display: When 115 VAC is supplied, the big display lights up toward the audience. This display is formed of planar gas discharge digits made by Beckman Instruments. They have a wide viewing angle of 130°, a spectacular legibility at 60 feet (18 meters) distance, and a life expectancy of ten years or more.

The Cabinet and Accessories: The EduCALC cabinet is an oak lectern which contrasts with the black face of the big display. It comes complete with a carrying case that doubles as a pedestal with which you can elevate the lectern above desk height. Also included with each EduCALC are the Owner's Manual and/or Application Handbook which are normally supplied with its master calculator.

The Interface Electronics: The EduCALC needs to electronically modify and amplify the signal levels and format of the pocket calculator display before they can be used to drive the big neon display. Medium Scale Integrated (MSI) circuits are used to demultiplex and buffer the calculator output. The engineering is conservative; each EduCALC is built and tested to function reliably for many years.

The Warranty: Each EduCALC is warranted against defects in materials and workmanship for one year from date of delivery.

Compared to computers, the EduCALC gives a really inexpensive teaching system. Students buy their own calculators, so the only expense is the EduCALC itself. Yet this system gets even more student involvement, more excited interest in the math.

This is a dramatic new sales, lecturing, and teaching tool. It costs no more than a good office typewriter. Many teachers have found that the money was readily available to them in budgets marked for "Innovative Projects" or "Curricular Development," as well as in the more customary "Audio Visual" or "Supplies and Equipment" accounts.

The price for the programmable model, the 25 GD, is $950 including delivery in the U. S. A. The 21 GD is $855, and the 22 GD sells at $920. There is a 15 day trial period during which you may return the machine to obtain a full refund if you are not satisfied.