Question 624539
Use the combination formula...


n C r = (n!)/(r!(n-r)!)


13 C 4 = (13!)/(4!*(13-4)!)


13 C 4 = (13!)/(4!*9!)


13 C 4 = (13*12*11*10*9!)/(4!*9!)


13 C 4 = (13*12*11*10)/(4!)


13 C 4 = (13*12*11*10)/(4*3*2*1)


13 C 4 = (17160)/(24)


13 C 4 = 715


So there are <font color="red">715</font> different pizzas you can make.