0 the symbol ( '' ) used, for example, to represent inches in measurements: --
Double prime and quotation mark tend to get used interchangeably in our digital world.
Single prime denotes feet and double prime denotes inches.
The double prime over the summation indicates that the first and last terms are to be multiplied by 1.
Just as there's a special character for a degree symbol, there are also special characters for prime and double prime symbols.
NYA ORD
European
May 10, 2021
DAGENS ORD
Shimmer
double prime