14
Decoding information
Textbook: pp. 36–38
GoalDecode encoded information and solve a simple number code and a Caesar cipher.
New words
decoding · dekodlashcipher · shifrtable · jadvalto shift · siljitmoq
Explanation
Decoding means turning encoded information back into its original form. For this we must know the code and the rule. In the table each letter has a number: A = 1, B = 2, D = 3, E = 4, ... K = 10, L = 11, M = 12, N = 13, O = 14, ... Q = 16, R = 17, T = 19. In a Caesar cipher each letter is shifted the same number of places along the alphabet.
Worked examples
Numbers 14, 13, 1: 14 is O, 13 is N, 1 is A. The word: ONA (mother).
Caesar cipher, 1 place to the right: in ALI, A becomes B, L becomes M, I becomes J. Code: BMJ.
Class activity
“Secret note”: each child uses the table to turn the first four letters of their name into numbers and gives them to a deskmate, who decodes them.
Practice
1
Decode: 10, 8, 19, 14, 2.
KITOB (book)
2
Encode the word “NON” (bread) with numbers using the table.
13, 14, 13
3
Decode OPO written with a Caesar cipher (1 place to the right). Move each letter 1 place back to the left.
NON (bread)