#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27, 16, 2);
const float e = 2.7182818284;

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.clear();  
  lcd.setCursor(0, 0);
  lcd.print(e, 4); 
}

void loop() {

}