Find the smallest positive whole number that when multiplied by 999 does not contain a 9 as one of its digits.

I checked up to 40 for you. Just take a calculator (I used the computer calculator) and do 999 x 41, 999 x 42 and so on until you get no 9's in your answer.

I had success at 999 x 112, by going through them one at a time. I might have missed one along the way.

To find the smallest positive whole number that when multiplied by 999 does not contain a 9 as one of its digits, we can start by checking the first few multiples of 999.

In general, to check if a number contains a 9 as one of its digits, we can convert the number to a string (or convert it to a list of its digits) and check if the string (or the list) contains '9'. If it does, then the number contains a 9 as one of its digits.

Let's start by checking the first few multiples of 999:

1 × 999 = 999 (contains a 9)
2 × 999 = 1998 (contains a 9)
3 × 999 = 2997 (contains a 9)
4 × 999 = 3996 (contains a 9)
5 × 999 = 4995 (contains a 9)
6 × 999 = 5994 (contains a 9)
7 × 999 = 6993 (contains a 9)
8 × 999 = 7992 (contains a 9)
9 × 999 = 8991 (contains a 9)

We can see that the first nine multiples of 999 all contain a 9 as one of their digits. Therefore, the smallest positive whole number that when multiplied by 999 does not contain a 9 as one of its digits is the 10th multiple of 999.

10 × 999 = 9990 (does not contain a 9)

So, the answer is 9990.