Kakuro

In this game there will be a grid of randomly placed blank squares, a series of squares connected horizontally or vertically form a group, before each group...
is a block with a number on it. The object of this game is to fill in the squares with numbers from 1 to 9 so that the numbers in the groups do not repeat and that the numbers sum up to the number before the group. The faster you finish the game, the higher your score. When you are stuck, you can click the hint button to get some hints, but you will suffer a time penalty.

How to play sudoku games:

There is really only one rule to Sudoku: Fill in the game board so that the numbers 1 through 9 occur exactly once in each row, column, and 3x3 box. The numbers can appear in any order and diagonals are not considered. Your initial game board will consist of several numbers that are already placed. Those numbers cannot be changed. Your goal is to fill in the empty squares following the simple rule above.