- Your first homework assignment is due.
- The book is in! So we have a reading assignment: please read pp. 6-17 in your text for next time.
- Stacey wrote up the first card trick solution for us. Have a look!
- I'll be collecting solutions for the second card trick when we get there.
What did we deduce about
- the Babylonians and place value?
- the purpose of the table?
- the Babylonian's missing number(s)? (Zero, My Hero)
How would the Babylonians write these numbers (using places 1, 60, 3600, 216000, etc. -- powers of 60!)?
We can use trees, by the way....
- 3600
- 3601
- 573
- 14001
- 1000000
- I "shuffle the deck", then lay out eight cards, turned down.
- I tell my assistant to choose three consecutive cards, examine them, remember them, and put them back in place (and I'm not looking -- I swear!).
- I ask my assistant to sum them up (explaining about face cards, etc.), then I magically "read her mind", and tell her exactly what three cards she chose.
- Here are the cards, as I arranged them. How does the trick work? (There's one tremendously important mathematical term that makes this work....)
- Take a look at this Mayan lunar calendar:
(pdf)
"The Maya also made their own very accurate measurement of the solar year, putting it at 365.242 days. The latest computations give us the figure of 365.242198: so the Maya were actually far nearer the true figure than the current Western calendar of 365 days (which, with leap years, gives a true average of 365.2425)." From The Universal History of Numbers, by George Ifrah.
How can we make sense of the numbers that are appearing?
- How would the Mayans write the number we call 1729?
- I'll write something in Mayan, and you tell me what it is in our number system.
- What distinguishes the Mayans from the Babylonians?
- Let's do a few examples with Mayan numbers: write the
following in Mayan
- 37
- 694
- 1034
- 141664
