How do you write half of a number decreased by 17

Q1 how many whole numbers less than 1000 can be written as a product of 3 consecutive whole numbers? a)10 b)11 c)15 d)21 q2 how many whole numbers between 5000 and 6000 consist of four different digits that decrease from left to right? a)3 b)10 c)69 d)120