Question

Calculati: a)6!x13-5!x12 b)5!-1!-2!-3!-4! c)7!-6!+5!-4!

Answer 1

a)6!x13-5!x12 =1*2*3*4*5*6*13-1*2*3*4*5*12=120*78-120*12=120*(78-12)=120*66=7920
b)5!-1!-2!-3!-4! =120-1-2-6-24=87
c)7!-6!+5!-4! =5040-720+120-24=4416
x! x factorial=1*2*3*4*5*.......