Because you get 1 point per daily mission you do, up to a max of 6 per player.

If you don't do the missions you don't get the point.

Yes,we have 10 active players who do all 6 daily missions,but activity rise only by 7 points,not by 60.Or my math is wrong?

It only counts the past 3 days. So at 10 players with 6 pts a day for 3 days, 180 is the most you can reach. The jump from 173 to 180 must be because within the past 3 days some of your group members didn't quite earn all 6 pts

With your current number of active people you can get max 60 activity per day. Activity is measured for 3 days, so some of your people just didn't do their dailies, because you miss 7 points yesterday. You had 173 and now you have 180, because in last 3 days everyone have done their dailies

If you want to attend great ninja war you may consider making some alts, because you need at least 12 active people to have activity above 200. You may want to create 2/3 accounts with level 28 just to have those 5 points every day. (I'm not counting arena, because with accounts like that it'd be hard to win with them anyway, you c*ways ask people on training one for retreat to have full 6). With 2 alts on 28lvl you should be able to get 200+, but I'd not risk and create 3rd one just to be sure. Ofc you can play on them only on weekends.

Ty for explaining.I consider to make alt for a while now,but so far we manage to get that 200 activity.Its so sad that servers die so quickly.

Also, to add to what Tragiczny said .. 3-days activity points counting starts at Sundays 5am after the server refresh to Tuesdays 4:59am ..