Math Challenge for you math geeks.

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blackbrandt

That Darn College Student
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Hello, calling all math geeks. Try this little challenge, and tell me what your first answer is via PM (I don't want others to see your answer). This must be done as quickly as possible. Don't stop adding until you reach the end.
Here is an easy exercise that must be done in your head only. Do not use paper and pencil or a calculator. Try to add up the following numbers as quickly as you can. Take 1000 and add 40 to it. Now add another 1000. Now add 30. Add another1000. Now add 20. Now add another 1000. Now add 10. What is the total?
And remember, no calculator!
Matt

Did you get the edit? :)
 
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Here is an easy exercise that must be done in your head only.
Matt

This means no abacuses.
Getmore, I now curse you and your family for all eternity. All your ejection charges will turn into flea-fart charges. All your liners will burn through and get stuck in the case.
(You can repent by editing your post...)


I need to edit this to say PM me your first guess.
The trick is most people say 4090+10=5000.
So far no takers on the 5000. I have gotten 5 PM's.
 
I prefer the simpler math I do..

I have two sprockets. one with a 15" pitch dia, the other with an 8" pitch dia. they are 14.75" apart (give or take an inch..). What length of chain do I need?
 
This means no abacuses.
Getmore, I now curse you and your family for all eternity. All your ejection charges will turn into flea-fart charges. All your liners will burn through and get stuck in the case.
(You can repent by editing your post...)


I need to edit this to say PM me your first guess.
The trick is most people say 4090+10=5000.
So far no takers on the 5000. I have gotten 5 PM's.

That is so stuppid. I am not a math geek. Tag your it
 
I prefer the simpler math I do..

I have two sprockets. one with a 15" pitch dia, the other with an 8" pitch dia. they are 14.75" apart (give or take an inch..). What length of chain do I need?

66"?
 
Not bad.. 66.8-something.. depending on chain, I'd go 67". I'd also look at my adjustment slots, and move / alter as needed..

that's always a fun question to ask hi school students. Gives them an appreciation for applying math, especially geometry & trig!

Of course, we can ask: If we have a motor turning at 1500RPM, and we need to get it down to 700rpm, what is the ratio? then, with that ration, if we have a fixed dia; say 9", what size do we need on the other end? should it be bigger or smaller? And, if we get a cain / belt that is 72" long, how far apart do they need to be? What if we cannot have the two sprockets / pulleys more than 15" apart, how long a belt / chain do we then need?

Using a bicycle as the example really brings it to life! (Adjsut the numbers above to suit a bicycle, or a washing mashine, or.... )
 
Really, most people get tricked by this?

How about: what's the sum of the first 10000 natural numbers - go a head and use paper and a calculator if you want.
 
It's 5000.
Now quick, what is d^2y/dx^2 of (x^3-15x^2)/((x+7)^2)?

Sorry, I just got out of Calculus....
 
OK, another one. No calculators, abaci (!) or any other calculation devices except your head. (Yes, I am talking to you, sully.)
What is 111111111x111111111?
 
OK, another one. No calculators, abaci (!) or any other calculation devices except your head. (Yes, I am talking to you, sully.)
What is 111111111x111111111?

That one's easy if you know the trick...
 
what aboyut this massive 2-bit adder sitting in front of me? or excel? or... hehehe...

can I use an old 8086?

I remember in grade 1, the teacher was trying to explain numbers to us. 1 unit (stick) was '1'. The bunch of 10 units (sticks, bundled with an elastic) is '10', and 10x '10' units would be 100units (sticks). or 6 bundles would be '60' , etc.. I was trying to tell her she was wrong, that some of the '10' bundles only had 7 or 8 'units' (sticks) so it wouldn't be '100' (or 60, or whatever..). But she would'nt listen. And here I am, trying to correct her bundles by pulling a few apart, and adding to the short bundles.

I see now what she was trying to do, the point she was trying to convey. But at the time, to me, she wasn't correct.. Ahh, kids..
 
How about: what's the sum of the first 10000 natural numbers - go a head and use paper and a calculator if you want.

As a computer guy, my answer would probably be 10000 less than the answer given by many others. :)

Here's a non-math one for you ....

Pronounce the word "folk" out loud. Okay ... now say what the white of an egg is called?

-- Roger
 
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I believe that is 5000 x 10001 = 50005000

0 + 9999 (or 9999) +
1 + 9998 (or 9999) and so on 5000 times ....

So it is 5000 times 9999 or ..... hey ... what do you mean that I can't use a calculator?!!!! Okay it is ... 50005000 less 10000. :)

-- Roger
 
0 + 9999 (or 9999) +
1 + 9998 (or 9999) and so on 5000 times ....

So it is 5000 times 9999 or ..... hey ... what do you mean that I can't use a calculator?!!!! Okay it is ... 50005000 less 10000. :)
That depends on your definition of "natural". Some include 0, others do not. I was always taught the term "common" for positive integers, and "whole" for integers beginning with 0. According to the definition I looked up for "natural", it may or may not include 0. FWIW. YMMV. NABD.

Doug

.
 
5i (or 5j if you've done a lot of circuits)
 
What I would like to know is, why people who enjoy math and science are assigned labels like "geek" (re: the title of this thread) and "nerd", but those shirtless guys with their bellies painted blue, sitting in a stadium on a 40-degree day are "okay"??!?:confused2:
 
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