When we are using a format mask ( for example with TO_NUMBER function ) we have basically three options :
1 We can use the format mask as is, means the format mask will replicate the format of our data exactly. If we have 4 digits before the dot and two digits after the dot as our data, then format mask is exactly the same
2 The second case when the format mask is stretched out, it will also work
As we can see the mask has 5 positions before the dot and three positions after the dot, while actual data has 4 and 2 respectively. Leading and trailing zeros are not shown in this case
3 But, if you make your mask contracted it won’t work – be careful because many students just don’t pay attention to it and losing their points on their exam on this simple question
You can find a corresponding test about it in the Book