Subscribe to our newsletter. Also includes the history and operation of the abacus and other counting systems. The Abacus and Other Counting Systems Includes explanations of how the abacus works. Also includes the history and operation of the abacus and other counting systems.
Textbooks come with either audio CD's or cassette tapes.
Greece, Turkey, Italy, Egypt Unconventional tours led by university professors to Greece, Turkey, Italy, Egypt. For those who don't want the usual tour. Inc. All rights reserved.