Solution to Sudoku no 418

Here is my original version of the solution:

...and here is another version sent to me by Reina on Twitter. Her father worked it out with the help of an Excel spreadsheet:

Sudoku no 418 (Extreme)

Sudoku grader and solver

See answer

Solution to Sudoku no 417

Here is my original version of the solution:

...and here is another one, which Zarex Alvin Daria sent to me on Twitter:

Sudoku no 417 (Moderate)

Sudoku grader and solver

See answer

Solution to Sudoku no 416

Sudoku no 416 (Tough)

Sudoku grader and solver

See answer

Solution to Killer Sudoku no 4

Here is my original version of the answer:

...and here is another from Shoshi Dembinsky, a member of the Daily Killer Sudoku group on Facebook:

Killer Sudoku no 4

Usual sudoku rules apply i.e. each row, column and 3x3 mini-grid must have all of the numbers 1 to 9 exactly once. The puzzle is also divided into smaller areas called cages, which are surrounded by dashed lines. Numbers are not repeated within a cage. The number in the top left hand corner of each cage shows the sum of the numbers in that cage:

Killer sudoku solver

See answer 

Solution to Sudoku no 415

Sudoku no 415 (Diabolical)

Sudoku grader and solver

See answer

Solution to Sudoku no 414

Sudoku no 414 (Easy)

Sudoku grader and solver

See answer

Solution to Sudoku no 413

Sudoku no 413 (Tough)

If you managed to solve this, please add a comment below saying how long it took you.

Sudoku grader and solver

See answer

Solution to Sudoku no 412

Here is my original version of the solution:

...and here is another version from Mustapha Maazouz, a member of the Sudoku Puzzles Facebook group:

...and another, which Agus Triyono posted in the SUDOKU Facebook group:

Sudoku no 412 (Extreme)

Sudoku grader and solver

See answer

Solution to Sudoku no 411

Sudoku no 411 (Tough)

Sudoku grader and solver

See answer

Solution to Killer Sudoku no 3

Killer Sudoku no 3

There is a channel on YouTube called Cracking the Cryptic where they look at how to solve sudoku puzzles and crosswords etc. In this video the presenter works through Killer Sudoku Puzzle no 3, which you can see below:

Killer sudoku solver

See answer 

Solution to Sudoku no 410

Sudoku no 410 (Diabolical)

Sudoku grader and solver

See answer

Solution to Sudoku no 409

Sudoku no 409 (Easy)

Sudoku grader and solver

See answer

Solution to Sudoku no 408

Here is my original version of the solution:

...and here is another version from Mustapha Maazouz, a member of the Sudoku Puzzles Facebook group:

Sudoku no 408 (Diabolical)

Sudoku grader and solver

See answer

Solution to Sudoku no 407

Sudoku no 407 (Tough)

Sudoku grader and solver

See answer

Solution to Sudoku no 406

Sudoku no 406 (Tough)

Sudoku grader and solver

See answer

Solution to Killer Sudoku no 2

Killer Sudoku no 2

Usual sudoku rules apply i.e. each row, column and 3x3 mini-grid must have all of the numbers 1 to 9 exactly once. The puzzle is also divided into smaller areas called cages, which are surrounded by dashed lines. Numbers are not repeated within a cage. The number in the top left hand corner of each cage shows the sum of the numbers in that cage: 

Killer sudoku solver

See answer 

Solution to Sudoku no 405

Sudoku no 405 (Moderate)

Sudoku grader and solver

See answer

Solution to Sudoku no 404

Here is my original version of the solution:

...and here is another one from Mustapha Maazouz, who is a member of the Sudoku Puzzles Facebook group:

Sudoku no 404 (Extreme)

Sudoku grader and solver

See answer

Solution to Sudoku no 403

Sudoku no 403 (Tough)

Sudoku grader and solver

See answer