The Aztec Number System.The Aztecs didn't use number symbols like 1, 2, 3, 4, 5... Instead, they used dots and pictures to show numbers.

20 was a significant number to the Aztecs because it related to the Aztec calendar. Because of this, Aztecs tended to count up by 20s.

We've done a lot of work counting by 10s, follow this video to practise counting up by 20s.

https://www.youtube.com/watch?v=­hV4bmrkyVU 

Other important numbers were 400 and 8,000, I wonder if you can guess why?

Aztec numbers used to mark the child's age.

The Aztec Number System

The numbers 1-19 were represented by dots.

E.g.

1 =

2 =

3 =

8 =

9 =

10 =

17 =

18 =

19 =

20 was represented by a flag/banner symbol.

400 was represented by a feather.

8,000 was represented by an incense bag / pouch.

400 is significant because it is 20 x 20, and 8,000 is 20 x 20 x 20.

The Aztec Number System

Some more examples:

When the Aztecs needed to show numbers past 20, they would add with the symbols they already had.

For example:

20 = 1 = So 21 =

26 = 40 =

105 = 57 =

How many flags would you need to draw for 300?

The Aztec Number System

CHALLENGECan you show the following numbers using the Aztec number system:

1. 5 2. 9 3. 20 4. 13

5. 23 6. 27 7. 400 8. 401

1. 25 2. 40 3. 13 4. 43

5. 54 6. 120 7. 400 8. 440

1. 34 2. 62 3. 103 4. 140

5. 93 6. 155 7. 200 8. 462

Bonus challenge: Can you write yours, and your family's, ages?

You would need 15 flags to show 300!

The Aztec Number System

Tomorrow we will extend our learning about expressions ( < = >) by practising some questions using Aztec numbers.

Example:

19 Answer: 19 <

Your teachers look forward to hearing how you get on with this. If you have any questions, remember to email your teacher and ask. Have fun!