Crack the Code!

Age Range: 5 - 11

There are a number of different ways of making codes. The children seem to enjoy doing this kind of activity, and when they understand the idea, they can make up their own codes, and they can also make up new ways of making codes.

Larger versions of the following tables can be found below. These can be printed and photocopied for the children to refer to.

 
A B C D E F G H I J K L M
1 2 3 4 5 6 7 8 9 10 11 12 13
 
N O P Q R S T U V W X Y Z
14 15 16 17 18 19 20 21 22 23 24 25 26

3, 18, 1, 3, 11 __ 20, 8, 5 __ 3, 15, 4, 5!

D K Q Y V Z C F J R M P U
1 2 3 4 5 6 7 8 9 10 11 12 13
 
L A W I S X G T E N O B H
14 15 16 17 18 19 20 21 22 23 24 25 26

7, 10, 15, 7, 2 __ 21, 26, 22 __ 7, 24, 1, 22!

The above two tables are quite similar. The children should look at the numbers in the message (composed by the teacher beforehand), find them in the table, look at the letter found above each of the numbers and write these down to form a message (by the way, __ means "insert a space here").

The following table is a little different...

1
V
3
4
5
6
7
W
9
10
11
12
A
14
15
16
P
18
O
20
21
22
23
U
25
F
27
28
29
E
31
R
33
34
J
36
K
38
39
40
L
42
43
44
45
46
47
48
49
50
51
52
Q
54
55
S
57
58
C
T
61
62
63
B
65
66
67
68
69
70
71
72
73
74
G
76
77
78
79
D
81
H
83
84
85
86
87
N
89
90
M
92
Z
94
I
96
97
98
X
Y

59, 32, 13, 59, 37 __ 60, 82, 30 __ 59, 19, 80, 30!

The table is a grid showing the numbers from 1 to 100, although some of the numbers have been replaced by letters. The children should look at the first number in the code, find where it should be in the grid, and write down the letter that is in its space. Repeating this process should enable the children to work out the code.

All of these codes can be used as a Maths activity. For example, the message for the table above can be replaced by...

50+9, 8x4, 10+3, 60-1, 40-3 __ 6x10, 80+2, 10x3 __ 50x9, 20-1, 20+20+20+20, 15x2!

The children should therefore work out the answer to each of the sums (e.g. 50 + 9 = 59) and then continue as before.

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