This is an easy project to make but pretty challenging to solve. You spin the blocks until you have solved the math problem on each of all 4 sides. Here is a short video showing how it works.
You will need to know 'order of operation' to solve the problems. If you don't recall, here it is:
P - Parentheses first
E - Exponents (ie Powers and Square Roots, etc.)
DM - Division and Multiplication(left-to-right)
AS - Addition and Subtraction (left-to-right)
Another Way to Remember:
Please Excuse My Dear Aunt Sally
Ok, enough of the school lesson. I made this puzzle easier by only including Multiplication, Division, Addition and Subtraction. You can obviously shorten or lengthen the puzzle to change the level of difficulty.
I will give a free Instructables year long premium membership for the first person that can solve the math problem - post in comments. The numbers for the blocks, in random order, are shown in the Step 12.
Step 1: Tools/Materials
- Drill or Drill Press
- Bits (3/16" and 1/2")
- 2x4 by 8" Long
- Stencils (optional)
- Bungee Cord - 3/16" Diameter x 10" Long
Step 2: Cut Blocks
I made the blocks from a scrap piece of 2x4. I started by cutting the width into 1.5" strips. I then cut each block to 1.5" long. I used a stop block on the miter saw to speed up the process.
Step 3: Mark Center
Make lines between the corners to find the center.
Step 4: Center Punch
I found it's a little easier to drill holes if you start with a center punch.
Step 5: Drill Hole
Drill a 3/16" hole through each block for the 3/16" diameter bungee cord. Counterbore two of the pieces to capture the knots on the ends. After drilling, I sanded the blocks to break the sharp edges. I applied a light a coat of gray pickled stain to each block.
Step 6: Number/Symbols
A stencil from a craft store was used to paint the numbers on the blocks. My better half helped with this tedious step.
Step 7: Bungee Cord
This is a 10" long bungee cord with the ends (metal hooks) removed. I cut one end off the cord and slid both hooks off.
Step 8: Feed Cord Through Blocks
Start with one of the counterbored ends and feed the clipped end through the block as shown. Keep feeding the blocks per your solution key until you have all the blocks on the cord.
Step 9: Ends
The first end will have the clip from the bungee cord. Once you get to the last block, tie a knot to secure the bungee cord for the opposite end.
Step 10: Pictures
The first picture gives you a reference on size and includes 3 of my other instructables.
Step 11: More Pictures
No solutions shown :)
Step 12: Can You Solve It?
The picture shows the puzzle in a random position. Side 1 through Side 4 are the four sides of the block. Since you don't have the puzzle in your hand, you will need to follow this order. If this doesn't make sense, refer to the pictures of the puzzle.
Don't read the comments if you want to try to solve it yourself
Step 13: Excel Template
Attached is a MS Excel Template so you can generate new numbers. I also included an 11 block version. Enjoy.