Using a DFRobot Voltage Divider I'm reading on the DFRobot website to implement this Voltage divider: Analog Voltage Divider SKU: DFR0051

void setup() 
{ 
  Serial.begin(9600);
}
void loop() 
{
      float val;
      float temp;
      val=analogRead(2);//This divider module will divide the measured voltage by 5, the maximum voltage it can measure is 25V.
      temp= val/40.92;
      val=(float)temp;
      Serial.println(val);
      delay(1000);
}


Where does 40.92 come from? And even when printing only VAL it's something like 210 and I'm not sure what this is supposed to be. I don't get how to get the actual voltage of the battery etc. being measured? If it's divided by 5, why do you not multiply by 5 anywhere?
The unit measures a maximum voltage of 25v. When the measured voltage is 25v it divides it by 5 to present a maximum of 5v to the Arduino.  That is measured as a value of 1023 by analogRead(). If you divide 1023 by 40.92 you get 25.