This might seem silly but is there a "magic number" if two teams have the same win-loss record?

Number of games remaining + 1

When next season starts, the Yankees and Pirates will both have a magic number of 163 at one point

Yes, any team's magic number can be calculated as [number of season games+1] 163-team's wins minus the second place team's losses. In the event of a tie for first both team's magic numbers are the same (and will always be 1 more than the number of games remaining because if they remain tied there will be a one-game playoff to see who will go to the playoffs. Unless of course they are in the same division and the runner-up will be the wild card. Rather than playing that game the team with the better head-to-head results that season will be declared division champ whereas the other team will be the wild card. This is the only scenario in which a playoff game will not occur. It may even happen in this year's AL East race.)

Yes, the magic number would be the same for both of them. Once the Rays and Yankees get their number of games played equalized I think we'll see that once or twice down the stretch. They never show it but every team has a magic number until they are mathematically eliminated.

e.g. there's 10 games left in the season, both teams are 90-62, the magic number for both teams would be 11.

Yes, a magic number can be calculated between any two competing teams, even for a trailing team to eliminate the leader. It is merely a simple formula. The result is typically not considered interesting except for securing postseason berths, and so is rarely discussed, but MN can be used, say, for determining what your team of interest needs to do in order to nail third place, if you want to know that.

Despite the name, there is nothing mystic involved, just a bit of quite simple mathematics.

head to head. assume group 8 is battleing group 9 for the spot. indexed below are the standings a million- 20-0 2 19-a million 3 17-3 4 14-6 head to head 3-0 Winner 5 14-6 head to head 0-3 6 13-7 head to head a million-2 7 13-7 head to head 2-a million Winner 8- 12-8 head to head 2-a million 9- 12-8 head to head a million-2 group 8 makes it

Sure. It's just the same number for both teams. If they both achieve it they will simply wind up tied after 162...

Sure. They both share the same magic number. If it's a tie at the end they go to a one game playoff if a title is at stake.

I think so. If two teams are tied, just use the next worst team to compile the calculation.

I think during the season, unless you are the last place team or mathematically eliminated, you always have a magic number.

Yes there is and it would be the same magic number to clinch for both teams.

Yes. It's called a one-playoff tiebreaker game.