# When Does 11 pluse 2 equal 1 ?!

**Question:**When Does 11 pluse 2 equal 1 !?

My Fiance's Father Askd me this Today, and i have no clue exactly how to go about answering this, could someone please please help!Www@FoodAQ@Com

**Answers:**

The hours on a clock is a perfect example!.

11 plus 2 equals 1 under mod 12 arithmetic!.

What this means is that instead of having all the numbers 1, 2, 3 !.!.!. infinity you only have so many of them!. In mod 12, you have 0, 1, 2 !.!.!. 10, 11!. To map a number outside this range into one of these numbers, you take its remainder after dividing by 12!. So, 11 plus 2 is obviously 13, nobody is arguing that!. But dividing by 12 leaves remainder 1, so 11 + 2 = 13 = 1 mod 12!. Hours on a clock!.

Of course you can do mod any integer!. So, for example x mod 2 = 0 or 1!. It tells you whether the number is even (0) or odd (1)!. Or x mod 10 tells you the LAST digit of any number!. x mod 100, last two digits, etc!.

(This type of math is used ALOT in cryptology, or encryption schemes!. Basically instead of an equation having one answer, there are now infinite!. For example, 1001 = 901 = 871 = 131 = 31 = 1 mod 10!. You have no idea whether the real result is 31, 131, 871, 901 or 1001!. They're all equally likely!. This is an oversimplification, as modular arithmetic usually is taught extensively in the context of group theory, which follows linear algebra, which follows calculus)!.Www@FoodAQ@Com

11 plus 2 equals 1 under mod 12 arithmetic!.

What this means is that instead of having all the numbers 1, 2, 3 !.!.!. infinity you only have so many of them!. In mod 12, you have 0, 1, 2 !.!.!. 10, 11!. To map a number outside this range into one of these numbers, you take its remainder after dividing by 12!. So, 11 plus 2 is obviously 13, nobody is arguing that!. But dividing by 12 leaves remainder 1, so 11 + 2 = 13 = 1 mod 12!. Hours on a clock!.

Of course you can do mod any integer!. So, for example x mod 2 = 0 or 1!. It tells you whether the number is even (0) or odd (1)!. Or x mod 10 tells you the LAST digit of any number!. x mod 100, last two digits, etc!.

(This type of math is used ALOT in cryptology, or encryption schemes!. Basically instead of an equation having one answer, there are now infinite!. For example, 1001 = 901 = 871 = 131 = 31 = 1 mod 10!. You have no idea whether the real result is 31, 131, 871, 901 or 1001!. They're all equally likely!. This is an oversimplification, as modular arithmetic usually is taught extensively in the context of group theory, which follows linear algebra, which follows calculus)!.Www@FoodAQ@Com

11 drinks/2 people/1 babyWww@FoodAQ@Com

Hours on a clockWww@FoodAQ@Com

thats funnyWww@FoodAQ@Com