Janice Musfeldt, age11, of Buffalo Grove, I11., for her question:
HOW DOES A POCKET CALCULATOR WORK?
There are two types of calculators. One is electronic and the other is mechanical. It wasn't too many years ago that the mechanical type was the only one in use. It featured toothed wheels that served as gears. Although many can still be found working in offices around the world, they are no longer being manufactured.
Today's calculator is strictly an electronic wonder. It is a device that can add, divide, multiply and substract with complete accuracy and can perform with great speed.
Calculators are used for making calculations. They do the job almost automatically by using miniature electronic circuits. It's no problem for them to add up a column of figures or to subtract, divide or multiply. Some can also handle more complicated functions and are able to extract square roots and cube roots.
Some of the larger calculators today have what is called memory storage. With this added feature, the machine actually stores up for future use the numbers and instructions that are necessary for solving certain mathematical problems.
Large desk top calculators are used in many offices, but the pocket size model is the wonder of the 1970s. It is extremely popular because it is so convenient. It is not only portable and can be put into purse or pocket with absolutely no problem but it can also do all of the calculations necessary for such tasks as schoolwork and balancing a checkbook.
Minicalculators, in some models, can also be used to solve the most advanced engineering and scientific problems.
Electronic calculators have several types of output equipment which records and presents to the operator the information that has been gathered. Most models show the answer instantly in a window on the face of the calculator.
Output equipment on some calculators includes the production of tape that shows the numbers involved in the problem. With this feature, a permanent record of the results can be obtained, and it is also possible to check to see if correct information was fed into the calculator. This tape feature isn't included on too many pocket calculators, since it adds to the equipment's bulk.
One type of calculator, called a programmable calculator, handles complicated, multistep tasks that are usually done only by a small computer. It can do tough jobs by using numbers, programs and sets of instructions that tell the calculator what jobs to perform with numbers. Numbers and programs are fed in on a keyboard. On most, data can be stored for repeated use.
Programmable calculators are available both in desk top and pocket sized models and can be obtained with either tape or display output.