Hi gents, thanks for your help.
I use Libreoffice writer and the Czech keyboard.It seems that special characters are not very well understood when inserting text directly into the editor in MB.I am attaching the same post as .doc and .pdf documents.
The attachments contain text that I originally copied and pasted into MB.(with problems)
It can be seen that inserting this new way is without problems. I used a free program to convert to .pdf
>pdf 24 tools< https://tools.pdf24.org . However, the .doc format also transferred without any problems .

https://tools.pdf24.org

Hi gents,
thanks for help. Sorely I use LibreOffice Writer and Czech keyboard mutation..something went wrong.
I'll try to insert the post as a separate text now. I'll see if everything is transferred correctly.

Hi Doug just done the test again and it worked OK. It must have been an error on my part.

I did not know the German keybord had alternates to 2 etc on the key?
regards
Roy

TEST!
Roy: Re 'They work in Word but do not copy across to this site messages. Don't know why?'
10² 10³ copied over from my Winword using Copy and Paste.
(Control + c and Control + v).

Re Alt + number ...
Many thanks for the list👍
I found ...
Alt + 253 = ², Alt + 0179 = ³
Alt + 0253 = ý, Alt + 179 = │
BTW; Alt 168 = ¿ as you say, Alt 0168 = ¨
Cheers, Doug😎

Tomarack, for the moment settle for a partial solution.
If you write everything with your mobile phone there are no problems, if you write on your PC, then you can only use your mobile phone to change the superscript character after the unit of measurement.
To write: raised to the second (or to the square if you prefer), i.e. the number 2 superscript, simply hold down the number two for a while. Logically it applies to all numbers.
With the same system put the fractions.

Sorry, they were tests.
We all need to help Tomarack.

m³

m²

Tomarack, do you use a PC or mobile phone to write on this site?

Hi I was going to wait for the definitive solution!
I have used superscript i.e. like the small 2 for the squared maths symbol. They work in Word but do not copy across to this site messages. Don't know why?

The alternative character set is below.

It is activated from the right hand numeric set plus Alt etc. First you must activate the keys by pressing the top left key of these numbers labelled 'numlk' and it will light up. so alt 171 is ½. alt 168 is the Spanish upside down question mark ¿.
I could not find superscript or subscript characters! So further help needed.
Roy

https://www.tedmontgomery.com/tutorial/altchrc.html

Hi Tom
Re: I was not able to copy the math formulas from my editor correctly. How did you do it please?

No Rocket Science Tom😁I don't know what device or what Editor you are using but ...
I use a Windows PC and a German layout keyboard. See Pic 1.
Look at the keys for 2 and 3. At the bottom right of the keys you will see a small ² and ³.
These are accessed by simultaneously pressing the ALTGr key (to the right of the Space bar).
I have checked several other national layouts, including Czech see pic 2, and have either not found this feature or different characters are shown in different languages.
Pic 3 Swiss. Pic 4 UK English. Pic 5 US English. Etcetera!
Seems to be a feature unique to the German layout!?

But there are other ways😉
I know that it is possible (in a Windows system🙄) to create special characters by pressing the Alt key (left of the Space bar) and a 3 or 4 digit number.
For instance Alt + 225 produces ß, Alt + 0225 produces á.
All very interesting but not very useful unless you have the full list of character codes in your head. Which I don't😔
There is however a better way. Gotta go now so more later. Pic 6 should give you a hint.😉
Cheers, Doug😎