- (5 min) Mental Math
- Multiply 1/3 by 3/8 and reduce [1/8]
- Start with 125, multiply by 10, then subtract 50 [1200]
- What is the perimeter of a rectangle whose sides are 10 feet and 5 feet? [30 feet]
- What is the area of a triangle whose base is 8 feet and whose height is 6 feet? [24 sq. ft.]
- What is the decimal for 526 divided by 100? [5.26]

- (5 min) Review of homework #15 (<= 3 problems)

- (10 min) Introduce probability:

- Pass out the "Notes on Probability"
- Explain that probability has to do with the future. Contrast
it to statistics:

Past Future Statistics about things

that have already occurredProbability of things

happening in the future - Define probability as a fraction:

NUMBER OF THINGS YOU ARE LOOKING FOR ------------------------------------- TOTAL NUMBER OF THINGS

- Discuss maximum probability (1), minimum probability (0) and what they mean. Ask students for examples.
- Use examples in the handout to illustrate basic probabilities.

Use these additional examples, if you wish, and ask students to solve them:- Probability of pulling the 6 of hearts out of a deck of 52 cards. [1/52]
- Probability of drawing a blue marble out of the bag in the handout [5/7]
- Probability of drawing a blue or a red marble out of the bag in the handout [7/7 or 1]

Note: this discussion goes much better

if you bring things to illustrate probability

with you, like dice, cards,coins, or marbles.

One technique that I have used successfully

is to spread an entire deck of cards out on

the floor in a rectangle, with each suit

being a row. When you then ask students

for probabilities of drawing certain cards

or suits, they can see it pictorially

for themselves.

- (Remainder of class) In-class Exercise.

- Hand out homework as students successfully complete the in-class exercise.