In baseball, the "magic number" is the number of your team's wins and the next-best team's losses that clinch the division title. Despite the Cubs' 5-game losing streak this past week, (mitigated by the Brewers' three losses in the same period), the Cubs' magic number today stands at 19, with 23 games left. So 19 Cubs wins or 19 Brewers losses, or any combination thereof, means the Cubs go to the National League Division Series.
Still, one might have preferred the Cubs not drop five straight in September...