#include <LiquidCrystal.h>
int rs = 13, en = 12, d4 = 11, d5 = 10, d6 = 9, d7 = 8;
float num1;
float num2;
String symbol;

LiquidCrystal lcd(rs,en,d4,d5,d6,d7);

void setup() {
Serial.begin(9600);
lcd.begin(20,4);

}

void loop() {
lcd.setCursor(0,4);

lcd.print("1st num");
while (Serial.available() == 0){}
num1 = Serial.parseFloat();
lcd.clear();
lcd.setCursor(0,0);

lcd.print("Enter symbol");
symbol = Serial.readString();
lcd.print(symbol);

lcd.print("2nd num");
while (Serial.available() == 0){}
num2 = Serial.parseFloat();
lcd.setCursor(10,0);
lcd.print(num1);

//String answer = [num1] [symbol] [num2];
//lcd.print(answer);

delay(200);

}