Statistics say that only 50% of 5th graders in the U. S. understand place value but that over 90% of Japanese and Chinese children understand place value in first grade. In looking at why, it was discovered that in the Asian number system, numbers 11-19, for example, are called 1-ten, one through 1-ten, nine, instead of having unique names as we do in English. This is continued throughout all their numbers, going on with the twenties and so on, calling them 2-tens instead of our shortened version. This constant reinforcement of what the numbers actually stand for give the Asians an concept of place value at a very early age.
It is important to teach math so that they not only know how to manipulate numbers like addition and subtraction but also understanding the underlying place value structure. Play games where you call numbers by their "Asian names" as well as their English names.