urgent! pls... help me..

Depending on the level you are doing, there really isn't a way to solve it easily. There is no formula that I know of. In the game, you can't have the same number in the same box or in the same row or column. You have to work with the numbers they give you. If you are working in a book, use a pencil. If you are doing the electronic one, start at level one until you get the hang of it. Sometimes it helps to look at the numbers in the column or box you are working. Count using the numbers there and notice which ones aren't. See if the missing ones are in the same column or row. Then you can exclude those. You might get the electronic one for your nephew. It has different levels and there's no erasing.