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MathMagic Cycle 4: Level 4-6 Regular 

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CODING and DECODING

   You can make secret codes by letting numbers represent letters
   of the alphabet. We can let: Vowels: A=6, E=8, I=4, O=2, U=10, 
   *=0(ZERO)  Consonants: B=1, C=3, D=5, F=7, G=9, H=11, J=13, K=15, 
   L=17, M=19, N=21, P=23, Q=25, R=27, S=29, T=31, V=33, W=35, X=37, 
   Y=39, Z=41 
CODING 
   So, to Code the word CAT, we find the numbers for each letter. 
   Look up C. Its C=3. Look up A. Its A=6. Look up T. Its T=31. 
   So, CAT is 3  6  31.
DECODING 
   Now lets Decode a word and see what we get. Decode 5  2  9: 
   What is 5? 5=D. What is 2? 2=O. What is 9? 9=G. So, 5  2  9
   is DOG! 

EXERCISE I 

A) Code each below:        

   SPOON       MATH        COMPUTER 

B) Decode each below:

   23  8  21

   8  27  6  29  8  27

   29  8  3  27  8  31 

C) Code the name of your school. As you can see, if you have the
   decoder, coder can be a great way to send secret messages. Now,
   notice there are two kinds of letters, vowels (a e i o u) and
   consonants (all the rest). Notice that the vowels are coded with
   even numbers and consonants are coded with odd numbers. So,
   VOWELS=EVEN, and CONSONANTS=ODD. We can make our code better.
   Lets make: VOWELS = EVEN - 2,  and CONSONANTS = ODD + 2 
   Now to Code CAT: C is a consonant, so C = 3 + 2 = 5; A is a vowel,
   so A = 6 - 2 = 4; T is a consonant, so T = 31 + 2 = 33 
   So CAT is 5  4 33 

   Now, Decoding requires you to remove the code, and can be a
   little more involved. 

EXERCISE II

A) Code the Messages below using our new code

   MATH IS FUN

   SAY HELLO

   TWENTY FOUR HOURS 

B) Decode the Messages below using our new code

   3  4  23  4  23  4

   41  0  8  7  2  7  2  33!

   5  4  19  19  33  13  6  23  0  19  2  5  6   

Finally, we can really soup up our code by coding our message
   with our formulas, and then changing to the letters that come
   out. So CAT becomes C = 3 + 2 = 5 = D A = 6 - 2 = 4= I T = 31 +
   2 = 33 = V So CAT is now DIV in our new code. 

EXERCISE III 

A) Code these messages into a new word message.

   CODE WORD

   ELEPHANTS NEVER FORGET

   ZEBRAS ARE IN THE ZOO (can this be done?--if not, what can be
   done so that the code will be worked) 

B) Decode these messages into readable messages

   NATTIHA

   NAAV NA OP QISOT

   UJA GOMA OT V*Q TADSAV 
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