Darkozin wrote: .... tell me a good website where I can do online Kakuro puzzles ....
Here are three:
All three provide legitimate puzzles, i.e. each puzzle has a unique solution.
The first is by Michael Mepham, always a dependable source of quality puzzles. You can do it online or print it out. (Print it landscape to get a slightly larger diagram.)
The second generates new puzzles on demand, with user-selectable sizes and complexities. It works online only (the printout isn't very good).
The third, like the second, generates new puzzles on demand. As far as I know it can't be done online, but the printout is good quality. (Print it landscape, and print page 2 only.) However, these puzzles are a bit unsatisfying in their lack of numeric symmetry. There are lot of two-digit 3's and 4's, but hardly any two-digit 16's or 17's.