Help! I get a error

Projects Programming
1

i'm a newbie ,i want to make a Computer with using arduino.
but i get a error,
this is the code:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

long number1;
long number2;
char symbol;
long ans;

void setup() {
  Serial.begin(9600);
  lcd.begin(16,2);
  Serial.println("Welcome to the Number Computer V1");
}

void loop() {
  long _in;
  String Number = "";
  if(Serial.available()) {
    _in = Serial.read;
    Number += _in;
    if(_in == '/n') {
      number1 = Number.substring(0,6);
      number2 = Number.substring(7);
      symbol = Number.charAt(6);
      switch(symbol) {
        case '+' :
          ans = number1 + number2;
          break;
        case '-' :
          ans = number1 - number2;
          break;
        case '*' :
          ans = number1 * number2;
          break;
        case '/' :
          ans = number1 / number2;
          break;
      }
      Serial.print(number1);
      Serial.print(symbol);
      Serial.println(number2);
      Serial.print("Your ans: ");
      Serial.println(ans);
      lcd.setCursor(0,0);
      lcd.print(number1);
      lcd.print(symbol);
      lcd.print(number2);
      lcd.setCursor(0,1);
      lcd.print("Ans:");
      lcd.setCursor(4,1);
      lcd.print(ans);
    }
  }
}

i get this error:
sketch_apr19a:21: error: argument of type 'int (HardwareSerial::)()' does not match 'long int'
sketch_apr19a:24: error: cannot convert 'String' to 'long int' in assignment
sketch_apr19a:25: error: cannot convert 'String' to 'long int' in assignment

who can help me?

2 
    if(_in == '/n') {

Are you certain that slash is leaning the right way? I'm certain that it isn't.

    _in = Serial.read;

Function calls require ().

Serial.read() returns a byte. Why are you storing that byte in a long?

      number1 = Number.substring(0,6);
      number2 = Number.substring(7);

The compiler is right. You can't do this. A substring can only be stored in a String.

3

Tell us what you want to do, we can tell how to do that.
What is the serial data ? A number ?
There is a special function for that : Serial.parseInt() - Arduino Reference

The Serial.read() is a function, you must use the ()
The substring(..) operator on a string returns a string (a sub string), you can not assign that to a number that way.

PaulS replied when I was typing this, he also noticed the /n instead of \n