The Nepohualtzintzin (Nepo) (Náhuatl) is a pre-hispanic computer and numbering system which was destroyed by the Spanish during the conquest of the Americas. It was rediscovered in the 1950s by David Esparza Hidalgo. It has since been integrated, by Mexico's Secretary of Public Education, into the curriculum for bilingual bi-cultural education. The Nepo is a rich source of mathematical manipulatives and is a valuable tool in the teaching and learning of mathematics, as well as pre-hispanic culture and language. Sometimes mistakenly called an abacus, the Nepo is actually a matrix and capable of much higher functionality.

The Nepo represents the elaborate mathematical system which was created and developed by the first people of the American continents. One must learn a bit about its culture and language in order to understand the Nepo. This system was started by Olmec ancestors who designed an instrument to count and calculate similar to a "manual computer", with which you could add, subtract, multiply, divide, and perform higher calculations. Later, the Mayans perfected it and the knowledge passed to the Mexica (Aztecs), who used it to facilitate commercial exchange and for many other uses. Tenochtitlán/Tlateloco (Mexico City) has always had at its heart one of the largest mercados in the world, one which continues today as the Central de Abastos. Of course they would have had an advanced system to support that level of commerce and to calculate with great accuracy their astronomical observations.

The Nepo is compared to a "computer" for the large number of operations performed with it. It is a matrix, a set of maize "accounts" aligned in 13 rows, in each row there are seven accounts, and in total it has 91 accounts.91 is a sacred number. 1x91 is one season of the year; 2 x 91 is 182, the corn cycle; 3 x91, the gestation of a baby; 4x91 is a year.

Archaeological evidence show us that Nepos were used in the form of majestic bracelets. Representations of this system have also been found in the design of necklaces, frets, pyramids, astronomical observatories and monumental sculptures.

Children throughout the states of Mexico are currently being taught mathematics using this system of math manipulatives. Their teachers prefer it because the children learn math using logic rather than memorization and it fills them with knowledge and pride of one of the richest cultures in the world. The system is used successfully with Special Education children such as those who are blind or with down syndrome.

Master teachers, Ing. Carlos Carrillo Suárez and Lic. Sara Rocio Ruiz Galicia , the teachers of the teachers, have generously agreed to open their schedules to bring this ancient and modern knowledge, for the first time, to Arizona and the United States, to our very own South Mountain and Maricopa Community. Please join us.