Where is my # key in Windows 10 on my MacBook?

[WouterK3]

Where is my # key in Windows 10 on my MacBook?

I am using macOS X Mojave - 10.14.5.
On the Mac side it is available with <Option - right> - 3

Keyboard layout and region: UK

Windows 10 sees this combination as something different.
Using Win 10 in full screen.

Any suggestions?

 

[TonyC2]

try shift+3

 

[PhilS8]

Try right option 3 - not left option... Works on mine.