Code breaking using Trace Tables

Padlock #1:

The following code will help you work out the combination (code) to open padlock #1 (see below)

code = ""
FOR i FROM 1 TO 3
   digit = i * 2
   code = code + STR(digit)
NEXT i
OUTPUT(code)

Trace Table

	Line Number	i	digit	code	OUTPUT
+–	1			“”
+–	2	1
+–	3		2
+–	4			“2”
+–	2	2
+–	3		4
+–	4			“24”
+–	2	3
+–	3		6
+–	4			“246”
+–	6				246

Padlock

Input the combination on the padlock below and click on “Unlock?” to test your combination.

Padlock #2:

The following code will help you work out the combination (code) to open padlock #2 (see below)

code = ""
code = code + "9" 
code = code + "7"
code = code + "1"
OUTPUT(code)

Trace Table

Complete the following trace table to work out the 3-digit padlock code:

	Line Number	code	OUTPUT
+–	1

Padlock

Input the combination on the padlock below and click on “Unlock?” to test your combination.

Padlock #3:

The following code will help you work out the combination (code) to open padlock #3 (see below)

code = ""
code = code + "7" 
code = "4" + code
code = code + "3"
OUTPUT(code)

Trace Table

Complete the following trace table to work out the 3-digit padlock code:

	Line Number	code	OUTPUT
+–	1

Padlock

Input the combination on the padlock below and click on “Unlock?” to test your combination.

Padlock #4:

The following code will help you work out the combination (code) to open padlock #4 (see below)

code = 61 
IF code MOD 2 == 0 THEN
   code = code * 3
ELSE
   code = code * 2
END IF
OUTPUT(code)

Trace Table

Complete the following trace table to work out the 3-digit padlock code:

	Line Number	code	code MOD 2 == 0 ?	OUTPUT
+–	1

Padlock

Input the combination on the padlock below and click on “Unlock?” to test your combination.

Padlock #5:

The following code will help you work out the combination (code) to open padlock #5 (see below)

code = 24 
IF code > 20 AND code <= 10 THEN
   code = code * 3
ELSE IF code > 20 OR code <= 10 THEN 
   code = code * 10
ELSE 
   code = code * 4
END IF
OUTPUT(code)

Trace Table

Complete the following trace table to work out the 3-digit padlock code:

	Line Number	code	code>20 ?	code<=10 ?	OUTPUT
+–	1

Padlock

Input the combination on the padlock below and click on “Unlock?” to test your combination.

Padlock #6:

The following code will help you work out the combination (code) to open padlock #6 (see below)

code = 245 
WHILE code < 1000
   code = code + 200
END WHILE
code = code - 200
OUTPUT(code)

Trace Table

Complete the following trace table to work out the 3-digit padlock code:

	Line Number	code	code<1000 ?	OUTPUT
+–	1

Padlock

Input the combination on the padlock below and click on “Unlock?” to test your combination.