Sum Float problem!

Hey guys!
I am developing an application that register several prices such as combustible, diversions, food, transportation etc...
And in each listview i list the prices i got one textview in the corner that shows the sum of all the prices.
But i noticed one problem:
Everytime i edit or add a decimal number, the sum doesn t recognize it...
For example, in an item there's 250.0 (in euros) and when i click it an edittext appears with that exact value.
If i change it to 250.2... the listview shows that number but the Total (the sum) doesn t add 0.2...

Can anybody help me please?
I apreciate it! :)