How to add 2 numbers??

Answer 1

By using the plus sign.
Looks like: +

Example/
int sum = 5 + 2;

Answer 2

(in C++)

#include <iostream>
using namespace std;

int main() {

int a = 15;
int b = 10;
cout << (a + b);

return 0;
}

replace a, b, 10 and 15 with something of your choice

if you want the sum of what the user writes:

#include <iostream>
using namespace std;

int main() {

cin >> a;
cin >> b;
cout << (a + b);

return 0;
}

again, replace a and b with something of your choice

Answer 3

Something called plus sign.
Search it on Google...

And if you wanna get more complicated, check this.
https://code.sololearn.com/c31yeylQ5Dnt/?ref=app