Math on analog read wrong result

Question

I'm trying to execute a math of analog read but I get some weird result.. I searched about int and floats but didn't understand..

My code is :

#include <SevSeg.h>
SevSeg sevSeg;
int bitsChange = analogRead(A0) ;
float fuel = (923 - bitsChange) * 0.121065375;
sevSeg.setNumber(round(fuel));

Assuming bitsChange = 683, so fuel has to be after rounding 29, what I get is 39!!!!

I want to know why I get this result to learn about it..