Another simple math shortcut
May 10, 2022 09:11:13 #
May 10, 2022 11:57:59 #
Delderby wrote:
My own Math shortcut converts degrees C to degrees F as follows - double the degrees C then take off 10%, and add 32. Use nearest integers!
Example: 24C x 2 = 48. less 10% (5) = 43, add 32 = 75F.
Also - 16=61 and 28=82.
Useful for the oldies like me who were brought up on Fahrenheit!
Example: 24C x 2 = 48. less 10% (5) = 43, add 32 = 75F.
Also - 16=61 and 28=82.
Useful for the oldies like me who were brought up on Fahrenheit!
In aviation the shortcut for converting celius to Fahrenheit is Cx2+32. 15Cx2=30c+32=62F. I used 15C as this is the standard temp. in aviation for density altitude. So using your numbers 24Cx2=48C+32=80F. To convert back to celius it is the reverse: F-32/2=C; 62F-32F=30F/2=15C or 80F-32F=48F/2=24C. 59F is also used as a standard temp for density altitude so that conversion to celius is 59F-32F=27F/2=13.5C and not 15C. All this does is get you within a plus/minus of what the actual thermometer is reading
May 10, 2022 13:13:36 #
RiJoRi
Loc: Sandy Ridge, NC
MrBob wrote:
I prev. mentioned the Trachtenberg system of mathe... (show quote)
And of course it works the same if you move the decimal points. 4.5x4.5=20.25 (Just remember that decimal points are slippery little things that like to move around on their own!)
--Rich
May 10, 2022 13:49:27 #
Delderby wrote:
My own Math shortcut converts degrees C to degrees F as follows - double the degrees C then take off 10%, and add 32. Use nearest integers!
Example: 24C x 2 = 48. less 10% (5) = 43, add 32 = 75F.
Also - 16=61 and 28=82.
Useful for the oldies like me who were brought up on Fahrenheit!
Example: 24C x 2 = 48. less 10% (5) = 43, add 32 = 75F.
Also - 16=61 and 28=82.
Useful for the oldies like me who were brought up on Fahrenheit!
Me too.
May 10, 2022 15:09:41 #
marine73 wrote:
In aviation the shortcut for converting celius to ... (show quote)
I find this to be surprising. I have always thought that anything to do with aviation would be accurate, which of course your above shortcut isn't.
May 10, 2022 20:06:23 #
Delderby wrote:
I find this to be surprising. I have always thought that anything to do with aviation would be accurate, which of course your above shortcut isn't.
You can blame the FAA for making 15C/59F as the standard temp for a standard day. That seems to be when every thing works in harmony.
May 10, 2022 21:45:35 #
bikinkawboy
Loc: north central Missouri
And when everything aviation related is working in harmony, that’s good and one should not ask questions. When they aren’t in harmony, planes crash and people die. As the old timers said, never look a gift horse in the mouth. Or a harmonious moment.
May 11, 2022 03:32:44 #
marine73 wrote:
You can blame the FAA for making 15C/59F as the standard temp for a standard day. That seems to be when every thing works in harmony.
Yes - my shortcut says 15C x 2 = 30, less10% (3) =27. Add 32 = 59F.
With global temperatures ranging at least between -5C and 45C in the course of a year, that would make an average of 7 "standard days" per annum - hardly a "standard" to be considered. Might as well use 16=61.
I have lived my life with a motto - "beware the experts". When I was a little lad dentists told us to brush up and down, ten years later they said do not brush up and down as this forces food particles under our gums and causes gum disease - the biggest single reason for bolstering a dentist's business. That was a bit late for me.
May 11, 2022 06:02:38 #
Delderby wrote:
Yes - my shortcut says 15C x 2 = 30, less10% (3) =... (show quote)
The conversion always has been stated as F = 9/5 C + 32.
Loren - in Beautiful Baguio City
May 11, 2022 06:21:55 #
rlv567 wrote:
The conversion always has been stated as F = 9/5 C + 32.
Loren - in Beautiful Baguio City
Loren - in Beautiful Baguio City
Yes - I prefer KISS - my brain does "double it less 10%" more easily than "times nine and divide by 5".
May 11, 2022 07:38:31 #
RiJoRi wrote:
And of course it works the same if you move the decimal points. 4.5x4.5=20.25 (Just remember that decimal points are slippery little things that like to move around on their own!)
--Rich
--Rich
Too bad we did not go metric.... those little points are so easy to move...
May 11, 2022 09:13:52 #
Reuss Griffiths
Loc: Ravenna, Ohio
Delderby wrote:
My own Math shortcut converts degrees C to degrees F as follows - double the degrees C then take off 10%, and add 32. Use nearest integers!
Example: 24C x 2 = 48. less 10% (5) = 43, add 32 = 75F.
Also - 16=61 and 28=82.
Useful for the oldies like me who were brought up on Fahrenheit!
Example: 24C x 2 = 48. less 10% (5) = 43, add 32 = 75F.
Also - 16=61 and 28=82.
Useful for the oldies like me who were brought up on Fahrenheit!
-40F = -40C
May 11, 2022 09:21:37 #
Reuss Griffiths wrote:
-40F = -40C
Nice one - and I've just checked it out - the short cut worked.
May 11, 2022 13:03:44 #
marine73 wrote:
In aviation the shortcut for converting celius to ... (show quote)
A shortcut that I find quite effective is. “Hey Siri, how many degrees Fahrenheit is. . . .
May 11, 2022 13:15:11 #
raymondh wrote:
A shortcut that I find quite effective is. “Hey Siri, how many degrees Fahrenheit is. . . .
But then the HIDDEN fact checkers add your question to your Dossier and WONDER why you want to know...
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