camera track sensor size

Imaging Sensor Size 1/2.3" Size of the CCD or CMOS image sensor, usually measured in fractions of an inch (e.g., 1/1.8" or 2/3"). In general, the larger the sensor.

I tried dividing every witch way and I can not make the example 1/1.8 make 2/3 I get .55 not .66 so I’m doing it wrong.
My sensor is 1/2.3 how many mm is that?
School was so long ago. It really looks simple, like how do you miss it? id better get a bracelet for my wrist and put my address on it.
I got this off nikon cool pix specs

Forget about the maths involved you’ll get the wrong answer since ‘non standard’ inches are used, just look it up instead

Or if your camera documentation has full frame equivalents for your lens you could use that instead

Thanks again. I got it now.