Inca technology is still questioned today. The Incas carved over 12,000 miles of road, which had a relay runners mailing system. The Incas built huge building without cement or mud to stick it together. Incas carved stones, which could weigh over 200 tons, and they were so perfectly carved that it fitted together a knife's blade could not fit in between. The Incas had created a strong central government. The Incas were the first people to use brain surgery on others, successfully.
Many archaeologist and investigators underestimate the complexity of the Incas culture. The true is that they develop medicine cures and treatments, art styles, magnificent pottery, technology in many fields, weapons development. They master complex metalworking skills, war strategy, advance architecture and much more.
The Inca had many technologies, including Stone Cutting (which they were very good at), Agriculture, Astronomy, Mathematics, Medicine, Hydraulics, Architecture, Record-keeping and Military Tactics (according to www. peru-travel-confidential.com/inca-technology.html). They recorded their special events on Quipus. They had a major road system of over 16,000 miles. They also had bridges to cross over rivers, and Aqueducts to bring fresh water to them.
The Incas understanding of mathematics was remarkable. They were capable to create a calculator using the same principle of the abacus. It was call Quipu, and they use it for complex mathematic calculations; we still don't understand fully how they use it. But we know that it was use to keep track of goods, people, statistics and general wealth management of the entire kingdom.
We speculate in what they use the Quipu. But analyzing the Inca technology of the Quipu we understand how it works. The quipu has one main rope; several middle size ropes are tie to the main rope. From this middle size ropes a new set of smaller ropes are tie to it; creating a second level. Each rope was use to tie knots counting from zero to ten, with different knots for dozens, hundreds, thousands and so on.