A very good formula to calculate the combinations of a 2 team round robin
where n= # of teams
X (n-1)
___________
2
example 4 team round robin
n = 4
(4) X (4-1)
___________
2
= 6
thats the total number of combinations for the bet
so if you bet a $110 round robin it would = 660
and if you hit all 4 teams you would win 2400
if you hit 3 out of 4 then to calculate it it would be # of winners which would be 3 and you would just substitute that for n so
(3) X (3-1)
___________
2
= 3
so you would have won 3 of the 6 bets
$330
and a total return of 1200 for 660 invested