THE NUMBER 9 !

[noel shelleyParticipant @noelshelley55608]

Edited By noel shelley on 24/08/2021 13:20:34

[noel shelleyParticipant @noelshelley55608]

[Michael GilliganParticipant @michaelgilligan61133]

Brilliant

MichaelG.

[Nigel Graham 2Participant @nigelgraham2]

Hee-hee! I like it!

I'm baffled by the 5 o'clock one though.

How does the square-root of 9! = 6 as I read it; or come to that the square-root of 8! = 5?

Nor does it work by the factorial of the square-root of nine.

[duncan webster 1Participant @duncanwebster1]

(sqrt(9))! – 9/9

3! – 1

3*2*1 – 1 =5

Does Bodmas cover factorials?

Edited By duncan webster on 24/08/2021 15:14:08

[Ramon WilsonParticipant @ramonwilson3]

Ah! you'd need a calclator to turn that into real time

Nice one Noel

Tug

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Noel, very good, however I've not had course to come across the type of equations for 5, 7 or 9, the 7 one taken the longest time for me to figure out on one of my fraction capable calculators.

Regards Nick.

[SillyOldDufferModerator @sillyoldduffer]

If you got 601.3952191045344 for 5O'Clock, join my club.

Also, am I right in saying that the digits of the hours expressed in seconds always add up to 9?

e.g.:

1AM = 3600s so 3+6+0+0 = 9

4AM = 14400 so 1+4+4+0+0 = 9

9AM = 32400s so 3+2+4+0+0 = 9

11AM = 39600s so 3+9+6+0+0 = 18 & 1+8 = 9

Bound to be useful for something. Is there a prize?

Dave

[JourneymanParticipant @journeyman]

I agree, the 5 is a bit iffy, needs brackets as per Duncan's explanation. If you fancy the real thing for your workshop wall available at a nearby South American rain-forest for about 15quid.

John

[Nigel BennettParticipant @nigelbennett69913]

I'm sure there must be a much simpler expression for the 9 o'clock position, but I can't imagine what…

[Ady1Participant @ady1]

cool!

Engineers or mathematicians xmas pressie sorted too

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Journeyman on 24/08/2021 15:52:00:

I agree, the 5 is a bit iffy, needs brackets as per Duncan's explanation.

.

I suppose it’s fair … given that the ‘bang’ is outside the sqrt sign

MichaelG.

[duncan webster 1Participant @duncanwebster1]

pressed the wrong button

Edited By duncan webster on 24/08/2021 19:51:55

[Brian GParticipant @briang]

Posted by SillyOldDuffer on 24/08/2021 15:40:42:

If you got 601.3952191045344 for 5O'Clock, join my club.

Also, am I right in saying that the digits of the hours expressed in seconds always add up to 9?

e.g.:

1AM = 3600s so 3+6+0+0 = 9

4AM = 14400 so 1+4+4+0+0 = 9

9AM = 32400s so 3+2+4+0+0 = 9

11AM = 39600s so 3+9+6+0+0 = 18 & 1+8 = 9

Bound to be useful for something. Is there a prize?

Dave

Probably been won almost as soon as we started using base 10 with arabic/indian numerals Dave, as the sum of the digits of any multiple of 9 is always a multiple of 9, and 3600 = 400 x 9.

I just checked and the same thing seems to work in other bases such as Hex, so that the digits of multiples of F add up to multiples of F. I'm beginning to understand why I was put in the applied maths stream at school as this sort of thing just confuses me.

Brian G

Edited By Brian G on 24/08/2021 20:37:57

[pgk pgkParticipant @pgkpgk17461]

Trachtenberg speed system multiplying by 9
Which looks clumsy in the example until the rules are second nature but the whole system was apparently able to teach kids to calculate a 15 digit number x a 15 digit number in under a minute?

Link

https://en.wikipedia.org/wiki/Trachtenberg_system#Multiplying_by_9

pgk

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by Michael Gilligan on 24/08/2021 19:47:10:

Posted by Journeyman on 24/08/2021 15:52:00:

I agree, the 5 is a bit iffy, needs brackets as per Duncan's explanation.

.

I suppose it’s fair … given that the ‘bang’ is outside the sqrt sign

MichaelG.

Hi, this is how I did it on my calculator.

This is the only way I could get it on my calculator with any brackets, any other combination of brackets gave a wrong answer or a system error.

Regards Nick.

Edited By Nicholas Farr on 24/08/2021 21:37:38

[Nigel Graham 2Participant @nigelgraham2]

Thank you Duncan.

I'm glad I was not the only one who'd not spotted the invisible brackets that make it work. 

I've never seen a clock like that previously.

Anti-clockwise clocks yes.

A clock with its otherwise plain dial given coloured segments to show pub opening times, yes.

A clock with fancy single-digit sums though…. No. I like it!

Edited By Nigel Graham 2 on 24/08/2021 21:55:11

[noel shelleyParticipant @noelshelley55608]

Gentlemen I'm glad it has generated some thought and comment, BUT I can claim no credit for it ! It was sent to me by an old school friend who paid less attention in maths than me, he also sent the WHAT IS IT I posted some weeks ago. I felt it was worth sharing. Ah well, Time Flies. Noel.

[duncan webster 1Participant @duncanwebster1]

The 7 would be better as 9 – sqrt(9) + 9^0, which would be 9 – 3 + 1 = 7

The symbol for 0.99999……… in my young date was a dot above the 9, not a line

Anyone know where I can get one, apart from Journeyman's South American Rainforest, which I must admit I didn't get

[Grindstone CowboyParticipant @grindstonecowboy]

Duncan – it's also a big river. I'm assuming we aren't allowed to mention the actual website?

Rob

[Anonymous]

Posted by duncan webster on 24/08/2021 23:45:05:

The 7 would be better as 9 – sqrt(9) + 9^0, which would be 9 – 3 + 1 = 7

But unfortunately introduces the numeral " 0 " ….

[pgk pgkParticipant @pgkpgk17461]

The search phrase "Math Clock buy uk" throws up multiple retailers and many more variations.

pgk

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Peter Greene on 25/08/2021 01:50:58:

Posted by duncan webster on 24/08/2021 23:45:05:

The 7 would be better as 9 – sqrt(9) + 9^0, which would be 9 – 3 + 1 = 7

But unfortunately introduces the numeral " 0 " ….

.

… which sometimes goes by the alias (9-9)

MichaelG.

[not done it yetParticipant @notdoneityet]

Posted by Nigel Bennett on 24/08/2021 17:08:10:

I'm sure there must be a much simpler expression for the 9 o'clock position, but I can't imagine what…

Yep, I thought that, too. After all it is about the number 9. KISS principle and all that.

Now set about the minute hand?!

Duncan, Ama-zing or -zon.

[JourneymanParticipant @journeyman]

Of course if you have an aversion to 9's and prefer computers over maths there is always this version:

Available from the same source along with a few other strange ones. Digital binary is quite good!

John

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