Houston Astros First-Place Clinch Scenario

Houston's traditional magic number (relative to second-place Texas) is 69 + 22 - 71 + 1 = 21.
Houston's first-place clinch number is 20.
Houston must win 20 more games (91 total) to clinch first place.

If Houston wins 20 more games, their final win total will be at least 91.
The table below shows the best case scenario for each of the other teams if Houston wins 20 of their remaining 22 games and loses the other 2.
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 Houston' column gives the
minimum number of games that each team will lose to Houston if Houston wins 20 more games. Assuming that a team wins all of its remaining games except for
the games it loses to Houston, the resulting maximum number of wins is shown in the 'Maximum W' column.

Team             W	L	GL	Losses to Houston	Maximum W
Texas            69	71	22	               0	91 *See tie-breaking notes below.
Seattle          66	74	22	               0	88
LAAngels         53	87	22	               0	75
Oakland          54	86	22	       4 - 2 = 2	74

Tie-breakers:
Houston has won 9 game(s) against Texas and lost 4.
There are no games left in the series.

The table above shows that if Houston wins 20 more games (91 total), then they will finish the season in first place in the division.

To see that Houston's first-place clinch number cannot be less than 20, consider the following scenario in which Houston wins 19 more games (90 total) but does not finish in first place:

Team             W	L	PCT	GB
Texas            91	71	0.562	0.00
Houston          90	72	0.556	1.00
Seattle          72	90	0.444	19.00
Oakland          62	100	0.383	29.00
LAAngels         59	103	0.364	32.00

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
Houston          71	69	22	0.507	0.0
Texas            69	71	22	0.493	2.0
Seattle          66	74	22	0.471	5.0
Oakland          54	86	22	0.386	17.0
LAAngels         53	87	22	0.379	18.0

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

Houston has won the season series with LAAngels 7 games to 6.
Houston has won the season series with Texas 9 games to 4.
LAAngels has won the season series with Texas 8 games to 5.
Oakland has won the season series with Texas 7 games to 6.

LAAngels currently has 2 wins against Seattle and 4 losses.
  LAAngels wins 6 additional games against Seattle and loses 1.
  LAAngels wins the series 8 games to 5

Oakland currently has 5 wins against Houston and 4 losses.
  Oakland wins 2 additional games against Houston and loses 2.
  Oakland wins the series 7 games to 6

Oakland currently has 6 wins against LAAngels and 5 losses.
  Oakland wins 2 additional games against LAAngels and loses 0.
  Oakland wins the series 8 games to 5

Seattle currently has 9 wins against Houston and 2 losses.
  Seattle wins 0 additional games against Houston and loses 2.
  Seattle wins the series 9 games to 4

Seattle currently has 4 wins against Oakland and 2 losses.
  Seattle wins 5 additional games against Oakland and loses 2.
  Seattle wins the series 9 games to 4

Texas currently has 7 wins against Seattle and 3 losses.
  Texas wins 3 additional games against Seattle and loses 0.
  Texas wins the series 10 games to 3

Houston wins 15 games agains teams outside the division and loses 1.
LAAngels wins 0 games agains teams outside the division and loses 13.
Oakland wins 2 games agains teams outside the division and loses 7.
Seattle wins 0 games agains teams outside the division and loses 3.
Texas wins 19 games agains teams outside the division and loses 0.

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