How to round number in actionscript

how can I round number to up down or to the 0.5 using action script 3.0 for example

• 4.9 w开发者_如何转开发ill be rounded to 5
• 4.7 will be rounded to 4.5
• 2.4 will be rounded to 2.5
• 2.3 will be rounded to 2

thank you.

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How about

Math.round(2 * number_here) / 2

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z = Math.floor(n);
p = n-z;

if(p<0.25)
    ans=z;
else if(p>0.75)
    ans=z+1;
else
    ans=z+0.5;