On the Subject of Caesar’s Maths

You thought maths was hard enough? Well now it’s encrypted too.

  • This module will display three LEDs and a maths question, encrypted using a Caesar Shift cipher.
  • Use the formula below to determine the shift key.
  • Decipher the question using the concise table on the next page.
  • Select the button with the correct answer to the problem.
  • If the answer is a decimal, round down to the nearest integer.
  • Choosing an incorrect answer will cause a strike and reset the module.

Caesar Shift key formula:

((6a * bc) - d) mod 26

a = sum of digits in the serial number

b = number of batteries on the bomb + 3

c = number of green LEDs on the module

d = number of red LEDs on the module

Cipher translation table:

The top row shows the encrypted letter, and the left-hand column shows the shift key. The intersection will give the decrypted letter.

Shift key A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
0 a b c d e f g h i j k l m n o p q r s t u v w x y z
1 z a b c d e f g h i j k l m n o p q r s t u v w x y
2 y z a b c d e f g h i j k l m n o p q r s t u v w x
3 x y z a b c d e f g h i j k l m n o p q r s t u v w
4 w x y z a b c d e f g h i j k l m n o p q r s t u v
5 v w x y z a b c d e f g h i j k l m n o p q r s t u
6 u v w x y z a b c d e f g h i j k l m n o p q r s t
7 t u v w x y z a b c d e f g h i j k l m n o p q r s
8 s t u v w x y z a b c d e f g h i j k l m n o p q r
9 r s t u v w x y z a b c d e f g h i j k l m n o p q
10 q r s t u v w x y z a b c d e f g h i j k l m n o p
11 p q r s t u v w x y z a b c d e f g h i j k l m n o
12 o p q r s t u v w x y z a b c d e f g h i j k l m n
13 n o p q r s t u v w x y z a b c d e f g h i j k l m
14 m n o p q r s t u v w x y z a b c d e f g h i j k l
15 l m n o p q r s t u v w x y z a b c d e f g h i j k
16 k l m n o p q r s t u v w x y z a b c d e f g h i j
17 j k l m n o p q r s t u v w x y z a b c d e f g h i
18 i j k l m n o p q r s t u v w x y z a b c d e f g h
19 h i j k l m n o p q r s t u v w x y z a b c d e f g
20 g h i j k l m n o p q r s t u v w x y z a b c d e f
21 f g h i j k l m n o p q r s t u v w x y z a b c d e
22 e f g h i j k l m n o p q r s t u v w x y z a b c d
23 d e f g h i j k l m n o p q r s t u v w x y z a b c
24 c d e f g h i j k l m n o p q r s t u v w x y z a b
25 b c d e f g h i j k l m n o p q r s t u v w x y z a