From: Timothy Hunter <TimHunter@...>
Date: 2007-02-18T23:14:31+09:00
Subject: Re: modulus/division..

Derek Teixeira wrote:
> i tried to get a better understanding of the % method, so i just set up 
> a program to show me the results of the % of a number ...
>
> so i tried out the number 4.
>
> puts 4%1000
> puts 4%500
> puts 4%100
> puts 4%50
> puts 4%10
> puts 4%5
>
> and for everyline i got "4" as the remainder.. but when i tried these 
> with a calulator .. i only got 4 as a remainder for the 1000. when i did 
> the 4/500 i got a .008 .. so shouldn't the % be an 8?
>
>   
When I was in elementary school they taught us these words for division. 
Suppose you have 9 divided by 4. 4 is the "divisor". 9 is the 
"dividend". 4 goes into 9 2 times, so 2 is the "quotient", but since 4 
times 2 is only 8, there is 1 left over. 1 is called the "remainder". 
The modulus operator returns the remainder after dividing two integers. 
That is, 9 % 4 = 1.

So what is 4 % 5? 5 goes into 4 0 times. 0 times 5 is 0, so there is 4 
left over. 4 % 5 = 4. For 4 % 10, 10 goes into 4  0 times, with 4 left 
over. 4 % 10 = 4. Same for 4 % 50 and all your other examples.

For interesting experiments, use a divisor that is smaller than the 
dividend. 10 % 4 = 2. 12 % 3 = 0.

For more interesting experiments, use negative numbers.