From left to right the sum of the first 3 digits of a 4 digit number add up to 20 and is divisible by 3

8751

Step-by-step explanation:

Let's start with the first 4 digits. Possible solutions (for first three digits) could include 8+7+5.

Now we just have to find if that number (plus adding on another number) is divisible by 3.

Now, the rule for finding numbers divisible by 3 is: when each digit is added to the other ones, and then those digits added, then those ones, and so on, they equal a multiple of 3. So 27 is 2+7, which equals 9, a multiple of three. This works for everything (that I know of). So we already have 20, and the nearest multiple would be 21.

21-20 is 1, so we just add the one onto the end of the number, and we get our answer, 8751.

To double check, 8751 divided by 3 is 2917, so we have our answer!