Okay, I’ve been working on a Sodoku puzzle for hours and I’m completely stuck. Assuming my additions are correct, here’s where I’ve gotten hopelessly stuck.

Look for the 6 in the left middle box. Not hard to narrow down. Third column, sixth row.

Now you know which column in the left middle box has a 5 in it, which tells you where 5 in the left top box is. That in turn gives you the 5 in the right middle box, and then the 8 in the same box, and then you can easily get all the 8s in the puzzle. Then everything else should start falling into place.

If the 6 were in the first column, there would be no possibility for the third column to have a 6 (since there is already a 6 in the ninth row). So 6 must be in the third column, fifth or sixth rows. And 6 in the sixth row is ruled out in the center box and the right middle box, so that leaves sixth row for the third column.