My mom has her Master's Degree in mathematics, and taught Jr. High math for a good portion of her adult career. One thing I learned from her (and foreign exchange students) is that US public schools usually teach math in an abstract way. That is, with no connection to reality. It would be like me teaching you what sentence structure is, without teaching how to convey meaning. You might know grammar, but you wouldn't know how to speak or write what's in your mind.