Good constructive feedback. I thought about it, so one of the next days when I get time, I'll add a little 'Limit Width' button up on top. It'll be freeflow by default, but just one click for those who prefer a narrower format.
In Calculize:
a = 1/3
show a+a+a+a+a+a == 6*a
# => false
show pow 9,18
# => 150094635296999140
# should be: 150094635296999121
show 150094635296999122 - 150094635296999121
# => 0
In Python 2.6.1:
>>> p = 1.0/3.0
>>> p+p+p+p+p+p == 6*p
False
>>> pow(9,18)
150094635296999121
>>> 150094635296999122 - 150094635296999121
1
These minuscule rounding errors are inconsequential for most apps, but for math...