Калькулятор все время выдет ответ 0

#include <iostream>
 
using namespace std;
 
int ADDITION(int FirstNum, int SecondNum, int &Result)
{
    Result = FirstNum + SecondNum;
    return Result;
}
 
int SUBTRACTION(int FirstNum, int SecondNum, int &Result)
{
    if (FirstNum >= SecondNum)
        Result = FirstNum - SecondNum;
    else
        Result = SecondNum - FirstNum;
    return Result;
}
 
int MULTIPLICATION(int FirstNum, int SecondNum, int &Result)
{
    Result = FirstNum * SecondNum;
    return Result;
}
 
int DIVISION(int FirstNum, int SecondNum, int &Result)
{
    if (FirstNum >= SecondNum)
        Result = FirstNum / SecondNum;
    else
        Result = SecondNum / FirstNum;
    return Result;
}
 
int main()
{
    short int FirstNum, SecondNum;
    unsigned short int operation;
    int Result = 0;
    cout << "Hellow, you are using my calc(between 2 numbers)\n";
    cout << "What you want to do?( 1 - ""+""\n 2 - ""-""\n 3 - ""*""\n 4 - ""/"")\n \n";
    cin >> operation;
    cout << "Type the first number: \n \n";
    cin >> FirstNum;
    cout << "Type the second number: ";
    cin >> SecondNum;
    Result = 0;
    if (operation == 1)
        ADDITION(FirstNum, SecondNum, Result);
    else
        if (operation == 2)
            SUBTRACTION(FirstNum, SecondNum, Result);
        else
            if (operation == 3)
                MULTIPLICATION(FirstNum, SecondNum, Result);
            else
                if (operation == 4)
                    DIVISION(FirstNum, SecondNum, Result);
                else
                    cout << "Wrong choise!!\n";
    cout << "Result: " << Result << "\n";
    return 0;
}

#include <iostream>
 
using namespace std;
 
int ADDITION(int FirstNum, int SecondNum)
{
    int Result;
    Result = FirstNum + SecondNum;
    return Result;
}
 
int SUBTRACTION(int FirstNum, int SecondNum)
{
    int Result;
    if (FirstNum >= SecondNum)
        Result = FirstNum - SecondNum;
    else
        Result = SecondNum - FirstNum;
    return Result;
}
 
int MULTIPLICATION(int FirstNum, int SecondNum)
{
    int Result;
    Result = FirstNum * SecondNum;
    return Result;
}
 
int DIVISION(int FirstNum, int SecondNum)
{
    int Result;
    if (FirstNum >= SecondNum)
        Result = FirstNum / SecondNum;
    else
        Result = SecondNum / FirstNum;
    return Result;
}
 
int main()
{
    short int FirstNum, SecondNum;
    unsigned short int operation;
    int Result;
 
 
    cout << "Hellow, you are using my calc(between 2 numbers)\n";
    cout << "What you want to do?( 1 - ""+""\n 2 - ""-""\n 3 - ""*""\n 4 - ""/"")\n \n";
    cin >> operation;
    cout << "Type the first number: \n \n";
    cin >> FirstNum;
    cout << "Type the second number: ";
    cin >> SecondNum;
    
    if (operation == 1)
        Result = ADDITION(FirstNum, SecondNum);
    else
        if (operation == 2)
            Result = SUBTRACTION(FirstNum, SecondNum);
        else
            if (operation == 3)
                Result = MULTIPLICATION(FirstNum, SecondNum);
            else
                if (operation == 4)
                    Result = DIVISION(FirstNum, SecondNum);
                else
                    cout << "Wrong choise!!\n";
    cout << "Result: " << Result << "\n";
    return 0;
}