How do you complete Number-Grid Puzzles?

If you are referring to Sudoku, they are puzzles unrelated to math.

In fact, a sudoku puzzle could be made up of grids of nine celebrities instead of 9 digits!
The rule of the game (using digits) is to complete the grid so that every row, column and each of the 9 sub-squares of nine cells contain all the nine-digits, once and only once.
Different techniques are available for the different levels of difficulties of the puzzle.
Try for example:
http://www.palmsudoku.com/pages/techniques-overview.php

Number-grid puzzles, also known as fill-in puzzles or numerical crosswords, are a grid-based puzzle where you need to place numbers in empty cells based on given clues. Here's a step-by-step guide on how to complete these puzzles:

1. Understand the rules: Familiarize yourself with the specific rules of the number-grid puzzle you're working on. Different puzzles may have slightly different rules, so it's important to know the specific guidelines for the puzzle grid you have.

2. Analyze the given clues: Look for the numbers already provided in the grid. These numbers represent clues, and they dictate the solution. The clues typically provide information about the number sequence or patterns in rows and columns.

3. Start with the easiest clues: Begin by identifying any straight lines or obvious patterns that can be filled in immediately. Look for rows or columns with consecutive numbers, complete sequences, or cells that only have one possible number option.

4. Use deduction and logic: Work your way through the puzzle, using deduction and logic to fill in the empty cells based on the given clues and the numbers you've already placed. Look for intersections, where the information from one row or column impacts another. Eliminate options by considering the numbers already filled in a particular row or column and the possible numbers remaining for empty cells.

5. Make use of the process of elimination: As you fill in the grid, certain numbers will be ruled out for other cells in the same row, column, or block. Continually revise your possibilities and eliminate numbers that conflict with the clues and numbers already placed in adjacent cells.

6. Pay attention to number frequency and placement: Consider the number of times a particular digit appears in a row, column, or block. If a number already appears multiple times, it will help narrow down the options for empty cells.

7. Double-check your work: Once you have filled in all the cells based on the given clues, review the completed puzzle to ensure that each row, column, and block follows the rules and that no digits are repeated.

By following these steps and utilizing logic and deduction, you should be able to successfully complete number-grid puzzles. Remember, practice makes perfect, so the more you solve these puzzles, the better you'll become at recognizing patterns and applying logical reasoning.