\setcounter ¶Synopsis:
\setcounter{counter}{value}
Globally set the counter counter to have the value of the
value argument, which must be an integer. Thus, you can set a
counter’s value as \setcounter{section}{5}. Note that the
counter name does not start with a backslash.
In this example if the counter theorem has value 12 then the
second line will print ‘XII’.
\setcounter{exercise}{\value{theorem}}
Here it is in Roman: \Roman{exercise}.