This lesson plan may be used with Senior One students studying perimeter and area.
The city of Tenochtitlan, which was on the site of present-day Mexico city, was larger than any in Spain. Its markets were visited by 50,000 customers each day. The markets' stores were bulging with the rich products of the advanced Aztec civilization. A court of judges remained in session at the markets to peacefully settle disputes that arose between buyers and sellers.
To help keep accurate accounts for their extensive commerce, the Aztec had developed an efficient system of numerals and arithmetic. Aztec numerals were of two types. For commercial uses, the numerals were made up of dots, vertical strokes, and a zero symbol. For other occasions, more decorative numerals were used. Although the concepts of place value and a number base of 20 had been borrowed from the earlier Maya and Olmec Native Americans, the numerals were distinctly Aztec. For example, a small ear of corn was used for the zero symbol. Corn, or maize, was the material base of most Central American civilizations. Its use as the zero symbol shows how important the concept was to the Aztec.
Among the applications of Aztec mathematics, the records that registered land ownership were of special importance. Land records gave the boundaries, the area, and the market value of property. The Aztec government used these records to calculate the amount of tax that the owners had to pay.
Recently, comparisons were made between the Aztec land records and records
of the same farms that were drawn up by the Spanish conquerors. Although
Spain was a leader in European science and mathematics, the Aztec records
were more accurate. This may be because the Aztec unit of area, the square
quahuitl, was reliable and did not change from farm to farm. The
caballeria, the Spanish unit of area, varied considerably, perhaps
for political purposes. In addition, perhaps the Aztec had more practice
in planning cities and building pyramids that required accurate measurements.
A hands-on exercise would follow the above reading. Create a quahuitl
from Macramé cord. Cut it into 2.5 metre lengths. Give one quahuitl
to each group of two to three students. Each group would be assigned a
specific role. These roles are: farmers or tax collectors. Have the groups
measure a large area such as a parking lot, cafeteria or gym with the quahuitl.
A farm group and a tax group must measure each site. You want to be able
to compare the measurements. The activity should be debriefed at the end
to discuss the difficulties that arose for the group. The students would
then realize the difficulties that may have been encountered by the Aztecs.
You could have a student play a judge to settle any disputes with the measurements.
