Ah, OK.
If you want to keep the actions/opportunities in the summary line, but lose the unnecessary decimal places, you need to use format_number.
Let's say your format expression is like this:
format( '{1}% ({2}/{3})', (cnt_a / cnt_o) * 100, cnt_a, cnt_b )
To have it display without the decimal places, change it to this:
format( '{1}% ({2}/{3})', (cnt_a / cnt_o) * 100, format_number(cnt_a,0,false,false), format_number(cnt_b,0,false,false) )
I'm not sure why that is necessary in the summary expression, but it should help.
If you want to remove the actions/opportunities altogether just change the format type of the summary expression to 'Number'.