What is "K-6?"  For our international users:

In the USA educational system, Kindergarten through 6th grades or "K-6,"
encompasses the earliest school years.  It is also called "elementary
school".  The organization varies from state to state.  When I was a child
in New York state, the grades were as follows:

Grade    Age
  K       5
  1       6
  2       7       "Elementary School"
  3       8
  4       9
  5       10
  6       11


  7       12       "Jr. High School"
  8       13


  9       14
  10      15       "High School"
  11      16
  12      17