I define elementary school as grades 1 through 6, and high school as grades 7 through 12. This post is about what should be taught in elementary school.
I believe in the concept of a classical education. Children should develop the core strengths and skills needed for life. Specific practical skills can be learned later if a good foundation has been laid. I see three core skills and three core strengths that should be developed in elementary school.
Skill 1 - English. This includes reading, writing, and speaking. I haven't thought through the ideal way to do this.
Skill 3 - Scriptural Language. Every child should learn the language of their scripture. This serves two purposes. First, everyone should learn a second language and this easiest to do as a child. And second, children should understand their religion deeply, and this can only be done by reading their scripture in its original language. Muslims should learn Arabic. Christians should learn Greek. Followers of the Old Testament should learn Hebrew.
Strength 1 - Physical Strength. All children should play sports. This develops physical strength and coordination.
Strength 2 - Mental Strength. After long consideration, I concluded that the Game of Go is the best way to develop mental strength. All children should play Go just as all children should play sports.
Strength 3 - Moral Strength. Moral strength is gained through the study of religion. Each child should learn the religion of their parents. So the religions of the families of the school should be taught.
Science and history should not be taught in elementary school. These subjects should be left for high school.