Seattle Mariners First-Place Clinch Scenario

Seattle's traditional magic number (relative to second-place Houston) is 83 + 10 - 83 + 1 = 11.
Seattle's first-place clinch number is 10.
Seattle must win 10 more games (93 total) to clinch first place.

If Seattle wins 10 more games, their final win total will be at least 93.
The table below shows the best case scenario for each of the other teams if Seattle wins 10 of their remaining 11 games and loses the other 1.
For each team, the table shows the current record (number of wins (W) and losses (L)) and the number of games that team has
left to play (GL) in the regular season. Taking the schedule of games left to play into account, the 'Losses to Seattle' column gives the
minimum number of games that each team will lose to Seattle if Seattle wins 10 more games. Assuming that a team wins all of its remaining games except for
the games it loses to Seattle, the resulting maximum number of wins is shown in the 'Maximum W' column.

Team             W	L	GL	Losses to Seattle	Maximum W
Houston          83	69	10	       3 - 1 = 2	91
Texas            79	73	10	               0	89
Oakland          71	80	11	               0	82
Los Angeles      69	82	11	               0	80

The table above shows that if Seattle wins 10 more games (93 total), then they will finish the season in first place in the division.

To see that Seattle's first-place clinch number cannot be less than 10, consider the following scenario in which Seattle wins 9 more games (92 total) but does not finish in first place:

Team             W	L	PCT	GB
Houston          92	70	0.568	0.00
Seattle          92	70	0.568	0.00
Texas            81	81	0.500	11.00
Oakland          74	88	0.457	18.00
Los Angeles      70	92	0.432	22.00

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

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
Seattle          83	68	11	0.550	0.0
Houston          83	69	10	0.546	0.5
Texas            79	73	10	0.520	4.5
Oakland          71	80	11	0.470	12.0
Los Angeles      69	82	11	0.457	14.0

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

Los Angeles has won the season series with Oakland 9 games to 4.
Seattle has won the season series with Los Angeles 9 games to 4.
Seattle has won the season series with Oakland 7 games to 6.
Seattle has won the season series with Texas 10 games to 3.
Texas has won the season series with Los Angeles 8 games to 5.
Texas has won the season series with Oakland 8 games to 5.

Houston currently has 6 wins against Los Angeles and 4 losses.
  Houston wins 3 additional games against Los Angeles and loses 0.
  Houston wins the series 9 games to 4

Houston currently has 4 wins against Oakland and 6 losses.
  Houston wins 3 additional games against Oakland and loses 0.
  Houston wins the series 7 games to 6

Houston currently has 5 wins against Seattle and 5 losses.
  Houston wins 2 additional games against Seattle and loses 1.
  Houston wins the series 7 games to 6

Houston currently has 6 wins against Texas and 6 losses.
  Houston wins 1 additional games against Texas and loses 0.
  Houston wins the series 7 games to 6

Houston wins 0 games agains teams outside the division and loses 0.
Los Angeles wins 1 games agains teams outside the division and loses 7.
Oakland wins 3 games agains teams outside the division and loses 5.
Seattle wins 8 games agains teams outside the division and loses 0.
Texas wins 2 games agains teams outside the division and loses 7.

Combining the current standings with the wins and losses from the scenario results in the final standings listed above.
# Seattle Mariners' magic number
# Seattle's magic number
# Mariners' magic number
# MLB Playoff Race