[рони]

exvion,
выбери одну из функций )))

function a(n,s)
{ s=1/s;
  return (n*s).toFixed(0)/s
}
function b(n,s)
{ s=1/s;
  return Math.floor(n*s).toFixed(0)/s
}
alert(a(4.648,0.01)+" "+b(4.648,0.01));