20 in Mexica / Aztec
× 20
One flag.
HISTORICAL · GROUPS OF 20
Mexica / Aztec
Dots count units; flags represent twenty, feathers four hundred, and bags eight thousand.
Convert numbers- Place
- Central Mexico
- Period / variant
- 15th–16th-century manuscript tradition
EXAMPLES
42 · Groups of 20
Two flags and two dots: 20 + 20 + 1 + 1.
Worked example
Write 42 in Mexica / Aztec
Write the larger values first, from left to right. Each sign carries its own value; add the groups.
- × 20× 20
Write 2 flags worth 20 each: 2 × 20 = 40.
- × 1× 1
Write 2 dots worth 1 each: 2 × 1 = 2.
Check
2 × 20 + 2 × 1 = 42
Sources and notation notes
Meet the symbols
Each tile shows a sign and what it means. A sign can stand for a whole amount, such as 10 or 100.
- 1
- 20
- 400
- 8,000
How the symbols fit together
Count how many of each kind of sign you see, then add their values. This exhibit uses a simplified additive layout.
- Learn the values: a dot is 1, a flag is 20, a feather is 400, and a bag is 8,000.
- For 42, count the two flags first: 20 + 20 = 40.
- Count the two dots next: 1 + 1 = 2.
- Add the groups: 40 + 2 = 42. Each sign already carries its value, so you do not need a zero to hold an empty place.
400 in Mexica / Aztec
× 400
One feather sign.
8000 in Mexica / Aztec
× 8000
One bag sign.
42 in Mexica / Aztec
× 20× 20× 1× 1
Two flags and two dots: 20 + 20 + 1 + 1.
A linear arrangement is used for comparison here. Manuscripts arrange signs in relation to counted objects and use additional conventions. No zero sign is supplied.
History
Nahua scribes used numerical signs alongside images of objects and tribute goods. The Codex Mendoza and Matrícula de Tributos preserve examples of flags, feather signs, and bags marking large quantities. Their composition is connected to the records in which they occur; it is not simply a replacement font.
How to read it
Count how many of each kind of sign you see, then add their values. This exhibit uses a simplified additive layout.
- Learn the values: a dot is 1, a flag is 20, a feather is 400, and a bag is 8,000.
- For 42, count the two flags first: 20 + 20 = 40.
- Count the two dots next: 1 + 1 = 2.
- Add the groups: 40 + 2 = 42. Each sign already carries its value, so you do not need a zero to hold an empty place.
Limits
A linear arrangement is used for comparison here. Manuscripts arrange signs in relation to counted objects and use additional conventions. No zero sign is supplied.
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