Halloween Sudoku Puzzle to Use in the Classroom
How would you like to use an adorable Halloween sudoku puzzle as a fun classroom activity? This puzzle is designed for elementary-age students, and it can be used with older students for individual seat work after completing a math assignment, as an early-arriver activity, or as a separate assignment to teach logic skills. With younger students, it can be used as an activity for the entire class to work on and complete cooperatively.
Halloween Symbols Instead of Numbers
One of the delights of sudoku puzzles is the fact that they rely on logic, rather than on arithmetic skills; and so letters, Roman numerals, pictures, or symbols can be used in place of numerical digits. This Halloween sudoku uses Halloween clip-art designs instead of numbers. A ghost, spider's web, jack-o'-lantern, witch's hat, cauldron, skull and crossbones, witch's broom, spider, and witch's cat fill in the squares of the puzzle grid.
The children will not need to draw each object artistically in order to complete the puzzle. They may wish to use the following sketchy representations for each picture:
Quick Representations of the Clip-Art Symbols
It may even be possible to locate colorful stickers that can be used in place of each picture; or you could create your own in black and white by printing the original symbols on printable labels (such as those made by Avery).
The given symbols in this puzzle form the rough shape of a smiling jack-o'-lantern. Most standard puzzles use around 22-26 given numbers, depending on the difficulty level, and thirty are given here to make this puzzle suitable even for younger students. It is possible to solve the entire puzzle using only the slice-and-dice technique, but older students may notice instances where they can use other techniques too.
Halloween Sudoku Puzzle
Beyond Elementary Slice-and-Dice
This might be an excellent time for students to learn an alternate form of slice-and-dice, which I like to call "ghost" slice-and-dice, if they don't know it yet. (Yes, I call it by that name, no matter what time of year it is.) Using this technique, the solver notices locations where a specific digit clearly belongs in a certain row or column of a particular block, although the specific cell is not identified; but the ghost of that digit (or symbol, in this puzzle) can claim the entire column or row and thereby eliminate that column or row from consideration in other blocks (nonads), as you can see below in Figure 7.
Here's an example of the use of "ghost" slice-and-dice, beginning with the starting grid; you see how the ghostly 6's in the central block can lay claim to the entire sixth column, since a six must go in that column in the middle block. (You can even use ghost slice-and-dice to move past the stage shown in Figure 8 by using Ghost Sixes in Row 5, left block, to eliminate one of the Ghost Sixes in Column 6.)