Are 0.33 and 0.330 equal

Answer 1

Mathematically, yes.

In a scientific context, 0.330 has one more significant digit than 0.33, and this difference indicates that 0.330 represents a more precise measurement. The natural assumption, then, is that 0.33 and 0.330 are not the same, although they might be - that is, it's possible that the quantity measured as 0.33 might have been measured as 0.330 if a more precise measurement tool had been used, but it's also possible that the more precise measurement would have yielded a result like 0.331 or 0.329 instead.