This is the same as asking "how many ways are there to order 7 items?" which is equal to 7! = 7*6*5*4*3*2*1 = 5040
Or you can use the nPr formula to get nPr = (n!)/(n-r)! 7P7 = (7!)/(7-7)! 7P7 = (7!)/(0!) 7P7 = (7*6*5*4*3*2*1)/(1) 7P7 = 5040/1 7P7 = 5040 leading to the same answer