I have stated that I am a huge fan of living math, at least for the preschool and probably early elementary years.  Here is my proof it works.

Today, Samuel was helping in the kitchen.  My job was to make the corn pudding this year.  We needed to make three recipes. Each recipe calls for 12 saltine cracker crumbs.  So for part of the prep, I asked Samuel to put the right number of crackers in the gallon size zip lock bag.  He started with the first set of 12 - "One, two, three,....ten, (then he added two and without counting eleven) twelve."  Second set, he started with 4 crackers and then 3 and so forth always adding correctly, never with the same amount (in other words, not skip counting, but actual adding).  Third set was "Five, Ten, Twelve."  I have never drilled him in addition facts, we have never done an addition workbook, he just picked up this way of "counting" from exposing him to the daily activities involving numbers, and a few living books by Stuart J Murphy and some games. 

Yeah for Living Math!