Rounding numbers. They get it or are lost. From my experience, it depends on what camp you're from, "Camp 5 is in the Middle" (the way I was taught), or "Camp 0-9". The former is incorrect while the latter is more precise, and I'll explain why. While the rule to rounding is, "5 or more," rounding is dependent on knowing Place value (base 10) and not Natural numbers. In Place Value, we use DIGITS! ZERO IS A DIGIT and not a natural number! This is understood, I hope. To model this, aways use a num