Math 105 Extra Credit 1 2

Extra Credit Assignment 1

PENNY TRICK

Why does the penny trick shown in class work?

Carefully write up your detailed explanation of why the trick works.

Up to 5 homework points extra credit.

Extra Credit is not accepted late; no exceptions.

Here is a review of what we did in class:

Penny Trick (Courtesy Dr. Edward Burger, Williams College)

• Start with some pennies
• Give a volunteer all of the pennies and ask the volunteer to secretly put 1 to 3 pennies in their pocket.
• Have the volunteer compute the sum of the digits of the number of pennies they have left (e.g. for 15, 1 + 5 = 6) and remove this many pennies from their hand and put them in their pocket with the others.
• Ask the volunteer to put some pennies on the table.
• How can I always tell how many pennies remain in the volunteer's hand?

Extra Credit Assignment 2

Chapter 1.4 Mindscape 18 (p. 32 of the book)

Due Monday 10/29 at the beginning of class