Ancient world history series in #historicals contains:<br />The abacus (plural abaci or abacuses), also called a counting frame, is a calculating tool which has been used since ancient times. It was used in the ancient Near East, Europe, China, and Russia, centuries before the adoption of the Hindu-Arabic numeral system. The exact origin of the abacus has not yet emerged.<br />Chapters:<br />01:04 - content<br />01:14 - Invention of the Abacus<br />02:48 - Sumerians ancient Abacus<br />04:00 - Abacus in history of Rome, India, China and Greece<br />04:45 - How Abacus Works
