Question 604308
It turns out that the "(9 over 4)" refers to the combination 9 C 4, which is


9 C 4 = (9!)/(4!(9-4)!) = (9*8*7*6*5!)/(4!5!) = (9*8*7*6)/(4*3*2*1) = 3024/24 = 126


So 9 C 4 = 126


They just used different notation to represent the same idea. Let me know if this makes sense.