multiplexing voltage display

Beautiful. i didnt try the print the not number, because the first worked fine.

now that i have the physical printing semi-sorted, i moved onto the voltage calculation itself. it works perfectly fine, however, because i want to display to 0.1V, is there any method of 'rounding' that i could use to print a result (as seen by serial) of 2.55 to 2.6, and 2.54 to 2.5 for later integration onto the 7 segment displays?

here is the voltage snippit of coding

/*
result smoothing: http://www.arduino.cc/en/Tutorial/Smoothing
Voltage calculation: http://arduinotronics.blogspot.com.au/2011/03/monitoring-voltage-of-dc-battery-supply.html

*/

int VoltageIn = A5;

const int numReadings = 40;
int readings[numReadings];      // the readings from the analog input
int index = 0;                  // the index of the current reading
int total = 0;                  // the running total
int average = 0;                // the average




void setup()
{
Serial.begin(9600); // initialize serial communication with computer:                 
  // initialize all the readings to 0: 
  for (int thisReading = 0; thisReading < numReadings; thisReading++)
    readings[thisReading] = 0;  
}

void loop()
{
  total= total - readings[index];         // subtract the last reading:
  readings[index] = analogRead(VoltageIn);// read from the sensor:  
  total= total + readings[index];         // add the reading to the total:     
  index = index + 1;                      // advance to the next position in the array:  

  if (index >= numReadings)               // if we're at the end of the array...      
    index = 0;                            // ...wrap around to the beginning:                  
  average = total / numReadings;          // calculate the average:
  Serial.println(average);                // send it to the computer as ASCII digits
  delay(1);                               // delay in between reads for stability            


int val = analogRead(average); // read the value from the sensor
float volts = (average * 0.021965811965812); // calculate the ratio
Serial.println("Volts:");
Serial.println(volts); // print the value in volts
Serial.println("average value");
delay(400);
}

note: the value or 0.0219... was calculated manually as a constant to alter the calculated value to the true voltage