how many integers are divisible by 3 between 10 ! and 10 ! + 20 inclusive ?
"0 ! is divisible by 3 - the way i look factorials is that any number included will also be divisible by the product . 10,9 , 8,7 , 6,5 , 4,3 , 2,1 are all divisors of 10 ! there are 6 numbers between 10 ! and 10 ! + 20 that are divisible by 3 . hence b : 7"
add(divide(20, 3), const_1)