Question 154962
evaluate the expression: (1000!-999!)/998!

------------------------------------
Note: 1000! = 1000*999!
and 999! = 999*998!
---------------------------
Rewrite the problem:
(1000*999! - 999!) / 998!

----------------------------

= (999!)(1000 - 1)/998!

= (999*998!)(999)/998!

Cancel the 998! common to the numerator the denominator.

= 999*999

= 998001
======================
Cheers,
Stan H.