Any maths guru's out there?

[terravista]

Hi
I received this image of a clock (if the upload works) and it is all equations using the number 9.
All seem pretty straight forward except the 7 o'clock requires rounding up the be dead accurate, but the 5 o'clock requires explanation.
What does the excalamation mark do to the equation to make this work?
Cheers
Ian

[paceman]

not my explanation:

5 o'clock is the square root of nine (3), factorial (3x2x1 = 6), minus 9/9 (6-1 = 5).

7 o'clock, whose calculation works out to 6.99999..., with an infinite number of nines.


the exclamation point explained:

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. For example, 5 ! = 5 times 4 times 3 times 2 times 1 = 120

[terravista]

Thanks paceman.
Great explanation.
Who would have thought I went through so many years and never heard of factorials.
More research on factorials show that they may also be called "shrieks" or "bangs". Maths sound like more fun than doing logarithms and trigonometry using books with a million printed numbers back in the 60's.
Cheers
Ian

[gronk]

Sounds like some people don't go camping enough !!!!   

[paceman]

Sounds like some people don't go camping enough !!!!   

knowing some of this is partly how i pay for my camping...

[NewieCamper]

I remember back at school discovering that 69! into the calculator to ages to calculate and maxxed out the display. 70! gave an error. Or maybe it was 63!? Don't think I ever used that button for anything except not listening to the  teacher though.

[Barrabart]

I'm no maths guru.

In fact I easily make two thick planks look like a computer................. when it comes to maths anyway.... 

[edz]

Is that Big Bangs Sheldon's clock ... Why !!!

[muzza01]

The numeral nine 9 has special properties when it comes to maths.
Any number multiplied by 9 when disits are added together = 9

Eg 9 x 7 = 63.                         6 + 3 = 9

Eg 9 x 12 = 108                      1 + 0 + 8 = 9

Eg 9 x 149 = 1341                  1 + 3 + 4 + 1= 9

Eg 9 x 23456 = 211104.          2 + 1 + 1 + 1 + 0 + 4 = 9

Eg 9 x 987654 = 8888886       8 + 8 + 8 + 8 + 8 + 8 + 6 = 54.  5 + 4 = 9 

[KingBilly]

Plus you can do the nine times table simply by counting to nine.

9 x 1 = 9 that is the hardest one to do but you can use for fingers to help 

Now count down the rest of the table:
9 x 2 = 1
9 x 3 = 2
9 x 4 = 3
9 x 5 = 4
9 x 6 = 5
9 x 7 = 6
9 x 8 = 7
9 x 9 = 8

No count them again from the bottom up:
9 x 2 = 18
9 x 3 = 27
9 x 4 = 36
9 x 5 = 45
9 x 6 = 54
9 x 7 = 63
9 x 8 = 72
9 x 9 = 81

KB

[gronk]

knowing some of this is partly how i pay for my camping...

?  how so mate ??

[GeoffA]

Secondary school maths.

Nice clock....

[DannyG]

All seems pretty straight forward

Ian, If all that seems pretty straight forward then you are clearly more of a maths guru that most of us Nice clock though!

[koshari]

I always wonder if we had 4 fingers on each hand if we would be octal people?

 

[speewa158]

Time is something that hangs on the wall , a fad out of Switzerland given time might catch on .
lf your tired Sleep
 lf your hungry eat
lf your thirsty drink 
lf you have to go  , Go
                                                 

[brooke.fossey]

Love the clock.  Where can I get one?

[Symon]

Who would have thought I went through so many years and never heard of factorials.

I've only come across them when doing statistics.  I hate statistics, so I don't use them often

Where I really drew the line was with laplace transforms hated that stuff with a passion.

[GeoffA]

I've only come across them when doing statistics.  I hate statistics, so I don't use them often

Where I really drew the line was with laplace transforms hated that stuff with a passion.

I didn't enjoy calculus at all....wasn't any more enjoyable when the kids did it, either....

[Garfish]

I loved matrices, and the imaginary number i, which allows the square root of negative numbers to be calculated....

Oh and permutation and combinations when the ! Becomes all too common

[gronk]

Where I really drew the line was with laplace transforms hated that stuff with a passion.

Ha, even though I had very little exposure, hexadecimal was another form of  calculation that I never got my head around fully ..

[prodigyrf]

Long addition test for you and no cheating on Google. It's true in letter form (ignore the plus signs) so see if you can work out what numbers each letter represents to also make it true numerically.

FORTY
 +TEN
 +TEN
-------
SIXTY

And then when you've finished that simple task you need to tell me why my calculator can't work out the tangent of 90 degrees and who has been playing around with it and stuffed it up 

[prodigyrf]

And in case you've forgotten you don't get any marks for getting the right answer unless you can show how you got there 

[nackdog]

And then when you've finished that simple task you need to tell me why my calculator can't work out the tangent of 90 degrees and who has been playing around with it and stuffed it up 
[/quote]

Is your calculator in degrees or radians? Should be in your options menu.

[speewa158]

lv just reread the posted ,,,,l think l need  ,,,,,,no l do need  :cheers:after all that 

[Symon]

I didn't enjoy calculus at all....wasn't any more enjoyable when the kids did it, either....

Calculus is good if you have a good teacher, when I first learnt it in high school I really struggled, but in Yr 12 I got a better teacher and really got to like it.  The basic concept is rather simple, the way it is written (with all the different notations) is what makes it confusing.

I loved matrices, and the imaginary number i, which allows the square root of negative numbers to be calculated....

Oooo baby, now you are talking!  Kirchoff equations stuffed into a matrix, which spits out complex numbers like there is no tomorrow.  Love it.

Ha, even though I had very little exposure, hexadecimal was another form of  calculation that I never got my head around fully ..

It's just counting to 16 really, but since we don't have numerical symbols for 11-15 we use letters. i.e. 10=A, 11=B, 12=C, 13=D, 14=E, 15=F.  So "10" in hex is actually 16 in decimal.  It is easier to get your head around if you convert it all to binary first, and take 4 bit nibbles to convert to hex, and 3 bit nibbles to convert to oct, etc.

Is your calculator in degrees or radians? Should be in your options menu.

He's taking the piss.  Tan of 90 degrees is undefined.  Tan(90) = sin(90)/cos(90) = 1/0 and division by 0 is undefined.