Getting error like "wrong number of arguments (1 for 2)"



I m new to ROR. I am trying to run simple application on ROR using mysql
I am using Index page on which there are 4 fields on my form (id,
number_1,number_2,result)all are displayed in text booxes (here result
is number_1-number_2). I have only one table in database with 3 fields
for these 3 fields on forms((id, number_1,number_2). One of the field in
ID in my database (Primary key). Now I want to update values in fields
(number_1, number_2,result) when i will click on Update button on my
Form. How should I do this?

Please help me.