I'm not quite sure what you're asking, but one way that fractions (and by extension, ratios) are tricky is that a larger denominator gives a smaller value. Five

I'm not quite sure what you're asking, but one way that fractions (and by extension, ratios) are tricky is that a larger denominator gives a smaller value. Five is greater than three but a fifth is smaller then a third. I've seen my children struggling with this. "It's an error so common that I imagine it must be named by now." Not really an error so much as an attempt to mislead.