Uninformed math teachers should not teach our children.

This is a harsh statement but the truth. Every teacher that teaches our public school children should know the structure of our number system. This seem a lot, but it is not that much:
(a) Natural Number System -- 1,2,3,...
(b) Whole Number System-- 0,1,2,3,...
(c) Integers - ...-2,-1,0,+,1+2,+3...
(d) All of the operations of each
(c) The hardest of all the national numbers system- fractions and all four operations.
No elementary teachers should teach our children without all of the above.
We must teach our children all of the above in grades one through eight, and of course applications of each skill or concept.