File this one under "frustration" or "confusing".
It seems that our beloved ColdFusion rounds numbers with repeating decimals for you when doing division, even when you don't want it to. Consider the following equations:
40 / 55 = 0.7272727273
1.0909090909 / 0.7272727273 = 1.4999999999
(60 / 55) / (40 / 55) = 1.5
60 / 55 = 1.0909090909
The last line is what CF9 displays. Terrible.
When using numberformat(), it took me giving it a mask of 15 places to get it to show 1.499999999999998, If I dropped it to 14 places, it showed 1.50000000000000.
This makes CF unusable for exact math.