AMUSEMENT

MADDENING MIND-MANGLERS

Another Tennessee Teaser

Write the numbers from 1 through 9 in a vertical column. Now add 1 plus 2 and write the sum (3) to the right of 2. Then add that sum to the next number (3) and write its sum to the right, and so on. To start:

1

2 = 3

3 = 6

4 = 10

Etc.

1. How many sums (right-hand numbers) are not divisible by 2?

2. How many sums are not divisible by 3?

3. How many sums are prime numbers? 4. How many sums are in the Fibonacci Sequence (see right)?

Fun Fact: The Fibonacci Sequence is a fascinating numerical series found repeatedly in nature, such as in the logarithmic spirals of a nautilus shell. "Fibonacci" was the nickname of Italian mathematician Leonardo Pisano Bogollo (1170– c. 1250), who fifirst referenced the series that occurs when each new number is the sum of the previous two (0, 1, 1, 2, 3, 5, etc.). Fibonacci was also instrumental in helping to spread the use of Hindu-Arabic digits (1, 2, 3) throughout Europe in place of Roman numerals (I, II, III), in addition to many other mathematical accomplishments.

–courtesy of Morris Bowles, Cane Ridge, Tennessee

Down at the Well

Down at the Well 5. Cy had a 5-gallon pail, a 3-gallon bucket, and a full well. His wife needed exactly 7 gallons of water—no more, no less. How could he oblige?

Seeing the Light

6. How long would it take a ½-mile-long train to go completely through a ½-mile-long tunnel at 30 miles per hour? –courtesy of Roger Dutcher, Overland Park, Kansas