## Archive for November, 2011

### Quinteron anyone?

Wednesday, November 30th, 2011

- My son was born on the 17th of November.
- That can’t be true!
- Why not?
- 17.11.
- Yes?
- What’s their difference? What’s their sum?
- 6 and 28.
- Exactly!
- Exactly what?
- 6 and 28 are the first two perfect numbers.
- Perfect in what sense?
- The divisors of 6 less than 6 are 1, 2, and 3 and their sum is 6. And the divisors of 28 less than 28 is 1, 2, 4, 7, and 14 and their sum is 28.
- Amazing!
-Can you find an odd perfect number?
- I have never tried, but I am sure I could if I put my mind to it.
- Good for you!
- What else?
- A number is quinteron if the sum of its divisors less than it is 5 times the number.
- 5 is quinteron!
- Excellent! Are there more?
- Let me think!

Problem source: Estímulo del Talento Matemático.

### Quote

Wednesday, November 30th, 2011

Success isn’t a result of spontaneous combustion.  You must set yourself on fire. – Arnold H  Glasow

### Erase you way to the solution

Tuesday, November 29th, 2011

Illustration by Krieg Barrie

Erase 10 digits in the number 1234512345123451234512345 so the number that remains is as big as possible.

Problem source: Estímulo del Talento Matemático.

### Quote

Tuesday, November 29th, 2011

### When is the 20th?

Monday, November 28th, 2011

- In a certain year there were four Fridays and four Mondays in January.
- How exciting!
- On which weekday fell the 20th of January?
- Did you know that is my birthday?

### Quote

Monday, November 28th, 2011

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I’m no better than anyone else at understanding what makes people tick, particularly women. – Stephen Hawking

### Reflections

Sunday, November 27th, 2011

### Playful thinking

Sunday, November 27th, 2011

White to play. Can he avoid losing?

### Olympic march

Friday, November 25th, 2011

The participant from a country could march 3 in each row with the flag bearer in front, 4 in each row with the flag bearer in front, or 5 in each row with the flag bearer in front.

How many were marching?

For extra credit: Who carried India’s flag in the 2010 Winter Olympics.

### Quote

Friday, November 25th, 2011

If you can’t convince them, confuse them. - Harry S Truman