15 !=13 !*14*15
15 !/13 !=13 !*14*15/13 !=14*15
7 !=4!*5*6*7
7!/4!=4!*5*6*7/4!=5*6*7
14*15/5*6*7=2*3/6=1
Intrebari?
Ex2
14 !=10 !*11*12*13*14
14 !/10 !=10 !*11*12*13*14/10!=11*12*13*14*15
8!=5!*6*7*8
8!/5!=5!*6*7*8/5!=6*7*8
14!*8!/10!*5!=11*12*13*14*15/6*7*8=360360/336=10725