Answer:
9
Step-by-step explanation:
If you want the number to be divisible by three make sure the sum of all the numbers are divisible by three. Add all the numbers you have to see what they make.
3+4+2+8+4=21
So we just need to find the greatest number we can add to that to have it remain divisible by three. A number divisible by three is 30, and we can add 9 to 21 to make 30. Of course, there are other numbers we could add, but nine is the largest one-digit number that would work. Other smaller numbers include 3 and 6.
3+4+2+8+4+9=30
Now we check to see if our number is divisible by three
342984÷3 = 114328
114328 is a whole number so we know it's divisible.
