I will modify my original idea based on comments thus far: let the kids add the zeros as subscripts, but then tell them to round to the place value of the digit where there is a value in each number being added. So you would get

  3.14160  
+2.71828
  5.85988

The answer would then be rounded to 5.8599.

This method would mesh with scientific practice, and again, would create awareness of an idea that will come up in later math and science courses.

Better?

Last edited by Val; 12/16/13 03:37 PM.