6 Awesome Math Tricks That Will Make Your Life So Much Easier (Very useful for investors)

Business Insider ^ | 12/06/2011 | Eric Platt

[wordsofearnest]

Another rule of thumb: If after 15 minutes in a poker game you don’t know who the sucker is, it’s you.

[petercooper]

bttt

[ProudFossil]

The one I always liked was:
Buy low, sell high.
Simple isn’t it? (Much sarcasm on this)

[spankalib]

LOL!

[killermosquito]

I remember listening to all of those investment counselors tell me that I was losing money due to inflation because my money was safely tucked away in CDs. So I finally gave in and lost a small fortune (at least it was for me).

[loungitude]

.

[Lonesome in Massachussets]

Actually, “Buy low, sell high” is somewhat counter-intuitive. Most people chase highs, buy a stock when it is peaking. Nathanson explicitly originated that advice in his turn of the 20th Century classic, “The Rational Investor”.

[Lonesome in Massachussets]

Another interesting, but less useful trick than the rule of 11. (How offen do you need to multiply by 11 anyway?)

What’s the square root of:

12345678987654321 ?

Hint: It was instantly obvious to me the first time I saw it.

[ProudFossil]

Actually, “Buy low, sell high” is somewhat counter-intuitive. Most people chase highs, buy a stock when it is peaking. Nathanson explicitly originated that advice in his turn of the 20th Century classic, “The Rational Investor”.

I know the actual saying is buy high, sell low but I am an optimist (and generally have been able to avoid Nathanson's advice).

[Lonesome in Massachussets]

How many trailing zeros in 40000005!

40000005! = 40000005 x 40000004 x 40000003 x ... 2 x 1

10! = 3628800, two trailing zeros

16! = 20922789888000, three trailing zeros

Hint: You do not have to multiply to get the answer.

[ProudFossil]

Another interesting, but less useful trick than the rule of 11. (How offen do you need to multiply by 11 anyway?) What’s the square root of: 12345678987654321 ?

Isn't it half of 222,222,222?

[colinhester]

Bflr

[bvw]

Is the “it” that was immediately obvious the same as the “it” you saw? I have to ask because you used 2 “it”s. Me, I would have used

1

letting my fingers linger awhile on the button.

[Lonesome in Massachussets]

Good work. How did you get it? Using electronics takes the fun and challenge out of it. Now tackle my challenge in #11. I composed that myself, but I am sure someone else has thought of it as well.

Hint when you get the answer, you will know that you are correct.

[Lonesome in Massachussets]

It was obvious to me because I am familar with polynomial convolution. Let X = 10, and y = p(x) = a(n) x X^n + a(n-1) x X^(n-1) + ...+ a(0) x X^0.

Then y^2 = convolution( p(x), p(x)). Obvious?

[muir_redwoods]

Remember these three things and you’ll be able to figure dates and days of the week all year

It’s as easy as 1-2-3, and do you like your 9 to 5 job at the 7-11 and can you count by twos?

Start with the last day of February. 2/29 is a Wednesday in 2012.

So is 4/4, 6/6, 8/8/ 10/10 and 12/12. So is 5/9, 9/5 and 7/11, 11/7. Follow through to 2013 and 1/23 is also a Wednesday as was 3/21 in 2012.

The last day of February in 2013 is a Thursday; the day advances by one each year and by two in a leap year.

Most folks can figure a date and day if they know one in the month.

[ziravan]

Bfl

[ProudFossil]

Good work. How did you get it? Using electronics takes the fun and challenge out of it. Now tackle my challenge in #11. I composed that myself, but I am sure someone else has thought of it as well. Hint when you get the answer, you will know that you are correct.

I cheated. I asked my wife. She is the smart one .

[Bigh4u2]

None?