How to round down to nearest X number - pseudocode for VBScript

I'm trying to round down a number to the nearest say 15, 20, 30. ie

726 to the nearest 30 is 700

714 to the nearest 15 is 700 etc

VBScr开发者_如何转开发ipt code would be very helpful but pseudocode would also be a huge help!

EDIT: Sorry, I forgot to say, that 726 is really a time expressed as an int, ie 07:26. So this should be 07:00, not 690

EDIT Again: I'm just extracting the minute and using the code people have answered with. Hopefully this will help someone else too. Thanks!

Thanks

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Pseudo code:

diff = num mod nearest
return num - diff

So 726 mod 30 = 6

726 - 6 = 720

vbscript:

Function GetNearest(num, nearest)
    Dim diff = num mod nearest
    GetNearest = num - diff
End Function

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You listed a bunch of languages in your tags. I'm going with C#, but a more generic algorithm:

int n = 726;
int q = 30;
int r = Math.Floor(n / q) * q;

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another way to do it is just to use integer division: 726 / 30 * 30 = 720