Think of how you would do it…
Rather difficult to do with a program… you and I would focus our attention to the 7.. to the 6… to the 6… to the 6… etc.
3.456666667 3.45666667 3.4566667 3.456667 3.45667 3.4567 3.457 3.46
In Flash, you would want to loop through all the digits and ask whether they are greater than or equal to 5 if so the next is incremented. Also, interpretting where you wish to stop… tenths in this case.
Is this what you are looking for?
myText = Math.round(myText * 100) / 100;