The number of ways of giving 20 distinct oranges to 3 children such that each child gets at least one orange is ___________.

Number of integral solutions to the equation $$x+y+z=21$$, where $$x \ge 1,y\ge3,z\ge4$$, is equal to ____________.

The total number of six digit numbers, formed using the digits 4, 5, 9 only and divisible by 6, is ____________.

The number of 3-digit numbers, that are divisible by either 2 or 3 but not divisible by 7, is ____________.