C :: Working With Files / Struct And Manipulating Data

I have the following code and I am trying to do simple math calculations to the data. I need to take the car price (y) minus down payment (z) and then divide that quantity by 12 times "yearsx" That answer is then assigned to x. The problem is that x will not print the correctly!I also noticed that if I increase the "count" to amnything higher than the number on lines in the file, I get the correct value for x but only on the last set of the struct..my file reads as follows:

last_name first_name car_price down_payment years
johnson bill 10,000 2,000 3

When I printf the struct to the screen, i need to do the following:

x = (10,000 - 2,000)/(12*years);

but this is the math part that wont work. I have checked and doubled checked number types and I cant get it right.

Code:

#include<stdio.h>
#include<stdlib.h>
#define FILENAME "file.txt"
#define SIZE 100
}

[code]....