Round number up to the nearest multiple of 3

Question

Hay, how would i go about rounded a number up the nearest multiple of 3?

ie

25 would return 27
1 would return 3
0 would return 3
6 would return 6

thanks

Answer 1

    if(n > 0)
        return Math.ceil(n/3.0) * 3;
    else if( n < 0)
        return Math.floor(n/3.0) * 3;
    else
        return 3;

Answer 2

(n - n mod 3)+3

Answer 3

Here you are!

Number.prototype.roundTo = function(num) {
    var resto = this%num;
    if (resto <= (num/2)) { 
        return this-resto;
    } else {
        return this+num-resto;
    }
}

Examples:

y = 236.32;
x = y.roundTo(10);

// results in x = 240

y = 236.32;
x = y.roundTo(5);

// results in x = 235

Answer 4

if(x%3==0)
    return x
else
    return ((x/3|0)+1)*3

Answer 5

(((x - 1) / 3) + 1) * 3

no need to use floating point arithmetics.