Seattle Mariners First-Place Eliminiation Scenario
Seattle must win 26 more games (27 total) to avoid elimination from first place.
Here are the final standings in a scenario in which Seattle finishes in first place with 27 wins:

Team             W	L	PCT	GB
Seattle          27	135	0.167	0.00
Oakland          27	135	0.167	0.00
Houston          27	135	0.167	0.00
Los Angeles      26	136	0.160	1.00
Texas            26	136	0.160	1.00

Tie breakers
Seattle wins the series with Houston 7 games to 6
Seattle wins the series with Oakland 7 games to 6

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
Oakland          1	0	161	1.000	0.0
Seattle          1	0	161	1.000	0.0
Texas            1	0	161	1.000	0.0
Houston          0	1	161	0.000	1.0
Los Angeles      0	1	161	0.000	1.0

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

Houston currently has 0 win(s) against Los Angeles and 0 loss(es).
Houston wins 2 additional game(s) against Los Angeles and loses 11.
Houston loses the series 2 games to 11.
Houston wins 0 additional game(s) against teams outside the division and loses 109.

Houston currently has 0 win(s) against Oakland and 0 loss(es).
Houston wins 6 additional game(s) against Oakland and loses 7.
Houston loses the series 6 games to 7.
Houston wins 0 additional game(s) against teams outside the division and loses 109.

Houston currently has 0 win(s) against Seattle and 0 loss(es).
Houston wins 6 additional game(s) against Seattle and loses 7.
Houston loses the series 6 games to 7.
Houston wins 0 additional game(s) against teams outside the division and loses 109.

Houston currently has 0 win(s) against Texas and 0 loss(es).
Houston wins 13 additional game(s) against Texas and loses 0.
Houston wins the series 13 games to 0.
Houston wins 0 additional game(s) against teams outside the division and loses 109.

Los Angeles currently has 0 win(s) against Oakland and 1 loss(es).
Los Angeles wins 0 additional game(s) against Oakland and loses 12.
Los Angeles loses the series 0 games to 13.
Los Angeles wins 0 additional game(s) against teams outside the division and loses 110.

Los Angeles currently has 0 win(s) against Seattle and 0 loss(es).
Los Angeles wins 2 additional game(s) against Seattle and loses 11.
Los Angeles loses the series 2 games to 11.
Los Angeles wins 0 additional game(s) against teams outside the division and loses 110.

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

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

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

Seattle currently has 0 win(s) against Texas and 0 loss(es).
Seattle wins 0 additional game(s) against Texas and loses 13.
Seattle loses the series 0 games to 13.
Seattle wins 1 additional game(s) against teams outside the division and loses 108.

# Seattle Mariners' magic number
# Seattle's magic number
# Mariners' magic number
# MLB Playoff Race