## Archive for January, 2010

### Reflections

Sunday, January 31st, 2010

The world turns on symmetry — from the spin of subatomic particles to the dizzying beauty of an arabesque. But there’s more to it than meets the eye. Here, Oxford mathematician Marcus du Sautoy offers a glimpse of the invisible numbers that marry all symmetrical objects.

### Playful thinking

Saturday, January 30th, 2010

According to John Aubrey, cribbage was created by the English poet Sir John Suckling in the early 17th century, as a derivation of the game “noddy”. While noddy has disappeared, crib has survived, virtually unchanged, as one of the most popular games in the English-speaking world. The objective of the game is to be the first player to score a target number of points, typically 61 or 121. Points are scored for card combinations that add up to fifteen, and for pairs, triples, quadruples, runs and flushes. – More

Play it here.

### Aiming at distinction

Friday, January 29th, 2010

- Give me three distinct primes?
- In what ways distinct?
- Different.
- So you don’t want them to be easily perceived by the senses or intellect?
- Come again?
- Like in the expression ‘it had a distinct flavor.’
- No, I didn’t mean that. Just different would be fine.
- Should they be clearly defined?
- What?
- Like in the expression ‘at a distinct disadvantage.’
- No, thank you.
- To avoid any misunderstanding, did you have in mind that the primes should be very likely or probable?
- ?!
- Like in the expression ‘there is a distinct possibility that she won’t come.’
- I have a feeling that you are avoiding the problem.
- You are flattering me.
- So, will you give me three distinct primes?
- I am working on it.
- Good!
- One final clarification. Should the three primes be notable like in ‘it was a distinct honor and high privilege?’
- I have told you already. They should just be different. Forget distinct!
- When you say different, do you mean dissimilar, separate, various, or unusual?
- Try unusual!
- That’s a hard one. What about 11, 101, and 101111?
- Finally!
- Are they unusual enough?
- Add them and add to the sum their product.
- You mean 11 + 101 + 101111 + 11 * 101 * 101111?
- Exactly.
- I am done.
- Is the answer a prime?
- Any prime or an unusual one?

Problem source: Berkeley Math Circle Monthly Contest.

### Quote

Friday, January 29th, 2010

The reason there are so few female politicians is that it is too much trouble to put makeup on two faces. – Maureen Murphy

### Lost for words

Thursday, January 28th, 2010

I am sure you have had the same feeling like I had the other day. I was in a square room 13m and 17m from two of its opposite corners and 20m from a third corner when someone asked me how big the room was.

I was lost for words!

Problem source: Nick’s Mathematical Puzzles.

### Quote

Thursday, January 28th, 2010

Reality continues to ruin my life. – Bill Watterson

Wednesday, January 27th, 2010

As everybody knows, time flies. The algorithm below was constructed to find out how fast. How many years, months, and days have passed since, for example, man landed on the moon?

Feed the algorithm 27 January 2010 and 16 July 1969 and it spits out 40y 6m -4d while the correct answer is 40y 6m 11d.

Can you fix it or, much better, make your own algorithm?

FUNCTION AGE

SET DATE TO DMY

M.ageYear=0

M.ageMonth=0

M.ageDays=0

CurrentBirthDate=GOMONTH(_bDate,(YEAR(_chkDate)-YEAR(_bDate))*12)

tmpDate=CurrentBirthDate

M.ageYear=(YEAR(_chkDate)-YEAR(_bDate))

IF CurrentBirthDate>_chkDate

M.ageYear=(YEAR(_chkDate)-YEAR(_bDate))-1

M.ageMonth=0

tmpDate=GOMONTH(CurrentBirthDate,-12)

ENDIF

DO WHILE tmpDate <= _chkdate

IF MONTH(CurrentBirthDate)=2

IF YEAR(_chkdate)=YEAR(CurrentBirthDate) AND MONTH(CurrentBirthDate)=MONTH(_chkdate)

tmpDate=CurrentBirthDate

EXIT

ELSE

M.ageMonth=M.ageMonth+1

tmpDate=GOMONTH(tmpDate,1)

ENDIF

ELSE

M.ageMonth=M.ageMonth+1

tmpDate=GOMONTH(tmpDate,1)

ENDIF

ENDDO

IF _chkDate < tmpDate

IF MONTH(tmpDate)=2 AND day(tmpDate)!=day(_chkDate)

M.ageMonth=M.ageMonth-1

_DateString1=”{^”+allt(STR(YEAR(tmpDate)))+”/”+allt(STR(MONTH(tmpDate)))+”/1}-1″

tmpDate=&_DateString1

ELSE

M.ageMonth=M.ageMonth-1

_DateString1=”{^”+allt(STR(YEAR(tmpDate)))+”/”+allt(STR(MONTH(tmpDate)))+”/1}-1″

tmpDate=GOMONTH(tmpDate,-1)

ENDIF

ENDIF

M.ageDays=_chkDate-tmpDate

RETURN ALLTRIM(STR(m.ageYear))+”y “+ALLTRIM(STR(m.ageMonth))+”m “+ALLTRIM(STR(m.ageDays)) + “d”

The algorithm is written in FoxPro 9 and was found on the Internet. Note that Gomonth() returns the date that is a specified number of months before or after a given date, while Year() returns the year from the specified date.

### Quote

Wednesday, January 27th, 2010

The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I found it!) but ‘That’s funny …’ – Isaac Asimov

### Four-letter word

Tuesday, January 26th, 2010

- What on earth are you doing?
- I am trying to fit these words into a 4×4 grid of cells: MPMM, OMPM, OMPP, OOMO, OOMP, POOM, and POPM.
- How does it go?
- I find it hard.
- Could it be because a four-letter word is missing?
- Oh, yes! You are right.
- What is the word?

Problem source: Joe Konhauser via Math Central.

### Quote

Tuesday, January 26th, 2010

I always wanted to be somebody, but I should have been more specific. – Jane Wagner