You can add two numbers with a plus sign:

int num = 3 + 4;

Now the variable `num` has the value 7. As always, command lines end with a
semi-colon. You can also add variables and carry out multiple sums at once:

double a = 4.10009, b = 9.02, c = 15.0; double d = a + b + c;

The other basic arithmetic operators are used similarly:

int n1 = 3, n2 = 4, n3 = 8; int sub = n1 - n2; // subtraction int mul = n4 * n1; // multiplication int div = n3 / n2; // make sure the denominator is not 0 int rem = n3 % n1; // remainder (modulo)

Parentheses can be used to clarify order of calculations:

int parens = ((n1 + n2) * (n3 / n2)) % n1;

Sometimes you might want to change a variable by adding to (or subtracting from,
multiplying by, etc.) its current value. Suppose integer `n` has some value
and you want to increment its value by 3. The following is a valid statement:

n = n + 3; // adds 3 to the value of n

However, the designers of C++ added a more concise way of doing this: