Secret Codes
In these messages letters have been turned into numbers in this way.
So A is $1$, and also $27$, B is $2$ and $28$, and so on.
[There are $26$ letters in the alphabet so you just start again if you get a number higher than $26$.]
Can you change these numbers back into letters?
$10.1. 3. 11. - 1.14.4. - 10.9.12.12. - 6.5.12.12. - 4.15.23.14. - 20.8.5. - 8.9.12.12.$
In the next bit of code we have added $3$ to each letter-number and changed them back into letters.
Remember that when it comes to more than $26$ you need to take the $26$ from the number. So A is $27$ as well as $1$.
Can you sort it out?
SDW - D - FDNH, - SDW - D - FDNH, - EDNHU'V - YDQ.
In the next bit of code we have added $3$ again.
You ought to be better at it now!
VLQJ - D - VRQJ - RI - EODFN - ELRGV - LQ D - SLH
In the next piece of code we have taken $2$ off the letter number.
Remember, B is $28$ as well as $2$, so if in this code it has Z, it stands for B.
Can you sort this one out?
JGRRJC - ZMW - ZUSC - AMKC - ZJMU - SNRFC - QAFMMJ!
Can you make up your own piece of code like this?
You can take off two or add three to the letter-numbers or make up your own way of doing it BUT you must tell us what you have done to the letter-numbers, or we will never be able to read it!
If you found this easy you might like to try a harder version.
First you turn the letters into numbers as before. Then you add the special coding word (also in number form) then turn the whole thing back into letters. These are put into blocks of five letters, [not the word length]. Let's see how this works.
I'll use the Code word NRICH In numbers 14. 18. 9. 3. 8
I'll put the word "Maths" into the code. In numbers it is 13. 1. 20. 8. 19
So I add each letter and get 27.19. 29. 11. 27.
In letters this is ASCKA
In the message below code word NRICH is used again. So I will turn my sentence into numbers, and add the code word, and turn it back into letters in blocks of five.
What does it say?
HSUOW - OCBJZ - COOUW - ADRWB - ZWJFW - FFB.
Now for the really difficult bit!
This time there is a different coding word.
All I will tell you that it is from this list:
LEMON, CHAIR, EIGHT, HORSE, CAMEL, TIGER, TULIP
Can you uncode this message? It's hard!
OJGYX - HCVWP - VJAFZ - HTGXT - RVYIS - HUGMQ - HBEQK - ZPERE
Now can you make up your own piece of code like this?
You can add your own words BUT you must tell us what you have done to the letter-numbers, or we will never be able to read it!
That is the point of a Secret Code! It is what makes it secret!