The abacus was the "great grandparent" of many other kinds of counting machines, such as the adding machine, the cash register, the computer, and the electronic calculator. It's easy to see where we...
Counting like a computer
When you see a 1 and 0 together, you would say they stand for ten. But to a computer, they stand for two! We count with ten numerals---0, 1, 2, 3, 4, 5, 6, 7, 8, 9. But a computer uses only two, 1...
Eko, eno, esa
If you speak English, you start by counting, "One, two, three.. .." If you speak Spanish, you start by counting, "Uno, dos, tres. . . ." And if you speak Ashanti, a language of Africa, you start by...
The invention of nothing
One of the most important things ever invented was---nothing! But how can nothing be important? And how can nothing be invented? To understand, we have to go back to the abacus. To show the number...
A gift from Arabia
The numerals now used by Arabic-speaking people are not much like the ones we call Arabic numerals. Only the 1 and the 9 are like ours, as you can see in this multiplication table from a book written...
Fancy fingers
Have you ever seen a clock like the one in the picture below? The marks on the face of this clock are called Roman numerals. The Romans were people who lived in Italy long ago. We still use their...
Arrowheads, letters, dots
Babylonia was an important kingdom in the Near East about five thousand years ago. The Babylonians invented one of the first forms of writing, and wrote many texts on mathematics. They did their...
Fingers, flowers, and polliwogs
> As tribes became nations and villages became cities, people had more > things to keep track of than ever before. Merchants had to keep > records of the things they traded to other merchants. The...
Make your own abacus
An abacus is a lot of fun to use. And you can make one very easily. To make an abacus like the ones used long ago, you'll need forty pebbles and a piece of cardboard, wood, or stiff paper. With a...
The marvelous counting machine
Imagine that it is five thousand years ago and that you are a rich merchant in the ancient city of Babylon. You have a curly black beard and a purple robe with yellow fringe at the bottom. You're...
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