Wholesale whole-number murder and redemption

An extended mathematics metaphor:

Flowing under the pre-K through high school curriculum, like the ever-widening Mississippi, is a steady expansion of the number system and its corresponding basic operations.

Important milepost concepts and mathematical problems which are posed, deconstructed and solved throughout those years are like the flatboats and steamboats of Mark Twain's era which floated upon the Mississippi's waters.

One doesn't seek to control the river, because the number system and its operations exist in nature, but we can select what floats on it and where to travel.  Choosing when and how to introduce concepts, what problems to pose, and where they fit is the foremost responsibility of a standards and curriculum developer.