- Announcements:
- You have an assignment due
today.
- You also had a reading assignment, concerning "counting by partition": how did that go?
- Last time: counting
- Tallies -- make a mark for each one, and then hand it over
- Cairns -- a type of tally, only using stones to represent each participant
- One-to-One correspondence, usually with body parts. So pointing at a full set of fingers would mean "10" (but some civilizations may have pointed at a left hip to mean 26!).
- Counting by partition
- "Divide and conquer"
- Is this how folks learned to count big numbers:
Dividing sheep into two groups, keeping track of the remainder, and then reporting the result?
- Upshot: We can count with only two fingers!
- Today:
- Let's start with a little review:
- Count 31 sheep with partitions.
- If you send the string "0, 0, 1, 0, 1, 0, 1, 1, 1" to the king, how many sheep does the king think you have?
- Here's our "Question of the day":
Can we break down numbers using only two fingers?
- Now, on to the Egyptians! (What's this got to do with Egyptians?)
(source)
- A "Fun and Game" to begin: a visit from the Great Fraudini!
- How does the game work?
- Can you win at the game? You should be able to do it every time!
- Each of you will be part of a team of three, taking turns playing
the roles of contestent, Fraudini, and someone to check the
play.
- Here's the handout for the cards, if you want to print off another copy.
- It relies on the "binary doubling doodah": 1, 2, 4, 8, 16, 32, ....
- Now -- how about those Egyptians?
Links:
Website maintained by Andy Long.
Comments appreciated.