magic number
magic number
/ˌmædʒɪk ˈnʌmbə(r)/
1 a figure that has a special meaning
She needs to reach the magic number of 270 votes to win the White House.
Eighteen holes isn't a magic number for the average golfer.
2 (in baseball) the combined number of wins by the team currently in first place in the league and losses by the team in second place that must be reached for the team in first place to win the title
The Cardinals have won only three of eight, but reduced their magic number for clinching the division to four.