Need help in RegExp AS 3.0

Hi,

var str:String ="123+31+21-25*5";
var re:RegExp = /(\d+)/;
var results:Array = str.split(re);
trace(results)
// ,123,+,31,+,21,-,25,*,5,*/

//but if the string will be is ...
var str:String ="123.5+31.5+21-25*5";
var re:RegExp = /(\d+)/;
var results:Array = str.split(re);
trace(results)
//,123,.,5,+,31,.,5,+,21,-,25,*,5,

but i need to split like 123.5,+,31.5,-,21,5,*,5
Actually i do't want to split the Dot(.)... bcoz i need to some Math Calcilation According to the user inputs
Can any one help me for this issu