St. Louis Cardinals First-Place Eliminiation Scenario
St. Louis must win 27 more games (27 total) to avoid elimination from first place.
Here are the final standings in a scenario in which St. Louis finishes in first place with 27 wins:

Team             W	L	PCT	GB
St. Louis        27	135	0.167	0.00
Chicago          27	135	0.167	0.00
Pittsburgh       26	136	0.160	1.00
Milwaukee        26	136	0.160	1.00
Cincinnati       24	138	0.148	3.00

Tie breakers
St. Louis wins the series with Chicago 7 games to 6

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
Chicago          0	0	162	0.000	0.0
Cincinnati       0	0	162	0.000	0.0
Milwaukee        0	0	162	0.000	0.0
Pittsburgh       0	0	162	0.000	0.0
St. Louis        0	0	162	0.000	0.0

Next, we show how the remaining series of games plays out in the scenario:

Chicago currently has 0 win(s) against Cincinnati and 0 loss(es).
Chicago wins 1 additional game(s) against Cincinnati and loses 12.
Chicago loses the series 1 games to 12.
Chicago wins 0 additional game(s) against teams outside the division and loses 110.

Chicago currently has 0 win(s) against Milwaukee and 0 loss(es).
Chicago wins 7 additional game(s) against Milwaukee and loses 6.
Chicago wins the series 7 games to 6.
Chicago wins 0 additional game(s) against teams outside the division and loses 110.

Chicago currently has 0 win(s) against Pittsburgh and 0 loss(es).
Chicago wins 13 additional game(s) against Pittsburgh and loses 0.
Chicago wins the series 13 games to 0.
Chicago wins 0 additional game(s) against teams outside the division and loses 110.

Chicago currently has 0 win(s) against St. Louis and 0 loss(es).
Chicago wins 6 additional game(s) against St. Louis and loses 7.
Chicago loses the series 6 games to 7.
Chicago wins 0 additional game(s) against teams outside the division and loses 110.

Cincinnati currently has 0 win(s) against Milwaukee and 0 loss(es).
Cincinnati wins 0 additional game(s) against Milwaukee and loses 13.
Cincinnati loses the series 0 games to 13.
Cincinnati wins 0 additional game(s) against teams outside the division and loses 110.

Cincinnati currently has 0 win(s) against Pittsburgh and 0 loss(es).
Cincinnati wins 0 additional game(s) against Pittsburgh and loses 13.
Cincinnati loses the series 0 games to 13.
Cincinnati wins 0 additional game(s) against teams outside the division and loses 110.

Cincinnati currently has 0 win(s) against St. Louis and 0 loss(es).
Cincinnati wins 12 additional game(s) against St. Louis and loses 1.
Cincinnati wins the series 12 games to 1.
Cincinnati wins 0 additional game(s) against teams outside the division and loses 110.

Milwaukee currently has 0 win(s) against Pittsburgh and 0 loss(es).
Milwaukee wins 1 additional game(s) against Pittsburgh and loses 12.
Milwaukee loses the series 1 games to 12.
Milwaukee wins 0 additional game(s) against teams outside the division and loses 110.

Milwaukee currently has 0 win(s) against St. Louis and 0 loss(es).
Milwaukee wins 6 additional game(s) against St. Louis and loses 7.
Milwaukee loses the series 6 games to 7.
Milwaukee wins 0 additional game(s) against teams outside the division and loses 110.

Pittsburgh currently has 0 win(s) against St. Louis and 0 loss(es).
Pittsburgh wins 1 additional game(s) against St. Louis and loses 12.
Pittsburgh loses the series 1 games to 12.
Pittsburgh wins 0 additional game(s) against teams outside the division and loses 110.

# St. Louis Cardinals' magic number
# St. Louis's magic number
# Cardinals' magic number
# MLB Playoff Race