I took an accounting test for employment. Several questions had number sequences for example 333456. I was asked to pick from four choices which...

I took an accounting test for employment. Several questions had number sequences for example 333456. I was asked to pick from four choices which number was off by four digets or two digets or etc. But I don't understand. What difference would it make if the numbers differed by two, three or even four as the number still would not be correct. And I didn't know how to read the digets, from left to right? Or right to left? What is this procedure called so that I know what to study?