Decipher this - Letters, Numbers, and Cryptography for Kids

"Decipher this" is an excellent activity for emergent readers. This wheel of letters and numbers can be a helpful tool in the process of developing many phonological awareness skill, sound/symbol relationship, spelling, and finally, reading secret words. If you want to find out more about the reading skill, click here.

When it comes to secret words, there are some interesting facts we learned:

• A method of protecting information and communications through the use of codes is called cryptography.
• The word "cryptography" comes from the Greek "kryptos," which means "hidden, secret," and the Greek "graphein," or "to write." 
• One of the most ancient forms of encryption is letter substitution. For example: substitute the letters in your message with the next ones, like this: Xf mpwf uijt hbnf

 The key to our hidden messages were numbers. This is an excellent opportunity to get a bit deeper and to work on numeracy skills. You can teach the kid place value with two-digit numbers - tens and ones, or let them just say the numbers. We tried to read the numbers in German, Croatian, and English. German can be tricky :) Here, you can find more about numeracy skills. 

 However, learning all these concepts about letters and numbers is implicit. What children do is - playing super-agents who have to decipher secret words, that lead them to the treasure. In our case, the treasure was a new book, and this is how we played the game:

• Decipher the first word using the wheel.
• Read the word. It is the location of the next secret word.
• Find the next word and decipher it.
• Continue until you get to the last one, which reveals the location of the treasure. 

To make this wheel, you'll need:

• a protractor and a ruler
• a piece of construction paper
• a milk carton lid
• a toothpick

Step 1.

Draw one bigger circle out on construction paper. Within the circle, draw a smaller one, starting from the same centre. 

This is where a bit of maths comes in. First, we divided the full circle (360°) with the number of letters in the alphabet (30 in Croatian) and got 12° per field. Just to be clear - by "we" I don't mean my kids and I. Oh, no. It was my husband who helped me get the idea from my head to the numbers and draw it on the paper.  

Now, for English or German alphabet, it would be just under 14° (13.8). 

Mark the angles and draw the lines from the centre.

The bigger circle is for letters, and numbers go in the smaller one. There is no specific order for the numbers. This way, the kids had to focus on finding the number and corresponding letter.

Take another piece of construction paper and cut out a circle - the same size as the small one you draw in step 1. Make a small "window" through which you can see the numbers.

Glue the lid on the backside of the circle and pierce the toothpick through it. Put the smaller circle on top of the bigger one.

Step 6.

Write a secret message, and you're ready to play :)