Presentation on theme: "… a problem solving strategy"— Presentation transcript:
1… a problem solving strategy Tables & Patterns (3.7)… a problem solving strategy
2Example (try at your seats): Dodger Stadium: Radio broadcasters joke about the number of people who start leaving Dodger Stadium during the seventh inning of baseball games. One evening, during a particularly boring baseball game in which the Dodgers were trailing 6 runs after 6 innings, the fans began to leave at a record pace …After the first out in the top of the seventh inning, 100 fans left. After the second out, 150 fans left. After the third out, 200 fans left. The pattern continued in this way, with 50 more fans leaving after each out than had left after the previous out. The ridiculous thing was, the Dodgers tied up the game in the bottom of the ninth inning, and people still kept leaving early. The game lasted 10 innings (the Dodgers lost anyway) and the pattern continued through the bottom of the tenth inning. How many fans left early?
3Let’s organize the data … 4 innings x 6 outs/inning = 24 outs TOTALFirst thought …OutPeople leavingTotal People that left so farThis could take a while …
4Second thought … (have a student fill in this chart on the side board) Keep filling in the data …Out #123TotalBase fans leaving100100100Additional fans5050Additional fans50
5Sooo … One Pattern: … 24(100) + 23(50) + 22(50) + … + 1(50) = 16,200 24(100) + 23(50) + 22(50) + … + 1(50) = 16,200Another Pattern: …24(100) + ( … + 1)50 = 16, 200One thing we’re missing…What about the fans that left after the third out at the bottom of the tenth? Are they leaving EARLY?16, 200 – 1,250 =14,950(50) = 1,250
6Another Strategy: Systematic Lists A list generated through some kind of system.A System -Any procedure that allows you to do something (like organize info.) in a methodical way.
7Loose Change:Leslie has 25¢ in her pocket but does not have a quarter. If you can tell her all possible combinations of coins she could have that add up to 25¢, she will give you the 25¢.Many systematic lists are in the form of a table whose columns are labeled with the info. given in the problem. The rows are used to indicate possible combinations.? What’s the smallest # of dimes I can have ? … Let’s start there …DimesNickelsPennies
8Loose Change:Leslie has 25¢ in her pocket but does not have a quarter. If you can tell her all possible combinations of coins she could have that add up to 25¢, she will give you the 25¢.There are 12 possibilitiesDimesNickelsPenniesRemember that there is often more than one correct approach to producing systematic lists …