Hi there, just a quick post to check if the solution posted is actually correct. The solution in the video is 4. I think it’s 3.

Here’s the problem.

“One digit in a 10-digit number is missing. What is the maximum number of ways that the missing digit could be filled so that the final number is divisible by 3?”

What it means is that the sum of numbers must be divisible by 3.

If the sum equals 1 - the added number should be 2 to make it divisible by 3

if the sum equals 2 - we need to add 1

if the sum equals 3 - we need to add 0

if the sum equals 4 - we need to add 2

if the sum equals 5 - we need to add 1

if the sum equals 6 - we need to add 0

if the sum equals 7 - we need to add 2

if the sum equals 8 - we need to add 1

if the sum equals 9 - we need to add 0

for 10,11,17,2276 the logic is the same. Which means that the new number can only be 0, 1, 2.

What do you guys think?