January 29, 2009 "I never failed once. I invented the light bulb. It just happened to be a 2,000-step process." -Thomas Edison (after he was asked about his 2,000 “failed” attempts!)

January 29, 2009 Another homework note Section 2.3 (cont’d) – bases Exploration 2.9 – more bases

Homework note Since you will be teaching math, it’s vital that you write math correctly. What’s wrong with this: Ex: Add 5 and 7, then divide the result by = 12/4

2.3 (cont’d) Our class Alphabitia system is a “base 5” system. Typical notation for base 5: instead of A, B, C, D, A0, AA, etc., write 1 5, 2 5, 3 5, 4 5, 10 5, 11 5, etc.

2.3 (cont’d) When you see “321 5 ”, say “three-two-one base 5” Let’s count in base 5: 1, 2, 3, 4, 10, 11, 12, 13, 14, 20, 21, 22, 23, 24, 30, 31, 32, 33, 34, 40, 41, 42, 43, 44, 100, 101, 102, 103, 104,…

2.3 (cont’d) Ex: Explain your thought process for these. a)Convert into our usual (base 10) numbers. b) Convert into base 5.

2.3 (cont’d)

As you explore various bases, think about how they are similar to base 10. Can you see why some children have trouble learning the base 10 system?

Exploration 2.9 You will learn and practice with base 6, base 2 and base 16. Base 2: Important in computer science Also known as “Binary” numbers Base 16: Important in computer science, too! Also known as “Hexadecimal” numbers

Exploration 2.9 Base 6: just another base that can be used (I can’t see any particular reason why 6 was chosen here…)

Exploration 2.9 Read the introduction (pg 43). Do Part 1 #1a. Do Part 1 #2 (try this by yourself first, then discuss with your table) Repeat for Base 2 and Base 16 (typos in base 16 section) Questions?

Exploration 2.9 Work on Part 3: #2 & 3 and Part 4: #1, 2 & 4 (these are due on Tuesday)

Homework Read textbook pgs 109 – 118 Do the textbook problems listed online Exploration 2.9 Part 3: #2 & 3 Part 4: #1, 2, 4