Master Lock Combination Breaking

16. Can the combination of a Master Lock be found though manipulation? Recently a method of finding the combination of a Master Lock has been presented on alt.locksmithing. It seems there is a formula that relates the numbers in a combination to each other. The first and last digit of any combination will both have the same remainder when divided by 4, and the second digit's remainder when divided by 4 will be - or 2 from the first and third's remainder. For example, if you knew the last digit of the combination was 5, the first digit could be any digit that had a remainder of 1 when divided by 4 and the second number any digit with a remainder of 3 when divided by 4. This means given one number in the combination, there are only ten numbers that can be in each of the other two positions, and thus only 100 possible combinations given one number in the combination. And it turns out there is an easy way to find the last digit of the combination. On older Master Locks, ones where the arrow at the top is raised, simply pull on the shackle and turn the dial until it catches, that's the third number in the combination. On news locks with the recessed arrow, there are twelve places the dial will catch if you turn it while pulling on the shackle. Seven of these will catch between two numbers, ignore these, and find the the five that catch on a number. Four of these will end in the same digit, i.e, 1, 11, 21, and 31, the fifth end with a different digit, and the is the third number in the combination. This means that given the knowledge, time, and patience, anyone can find the combination and open your lock. But then so can anyone with a pair of bolt cutters, a hacksaw, or maybe even a hammer. These are three (US) dollar locks. They have many useful applications, but they are not high security locks. Plan your usage accordingly.

(i am sure this is just because they lost THEIR combination)