Arithmetic Operators

In JavaScript, you have the usual arithmetic operators:

1 + 2;  // add
9 / 3;  // divide
1 * 5;  // multiply
9 - 5;  // subtract
10 % 4;  // modulus (division remainder)

The / operator yields a floating-point result.

console.log(9 / 3);  // 3
console.log(1 / 2);  // 0.5

The % operator works with both integer and non-integer numbers.

console.log(42 % 10);  // 2
console.log(1.1 % 0.3);  // 0.20000000000000012

The ** operator is the exponentiation operator (similar to Python): it raises a number to a power.
```
console.log(2 ** 10);  // 1024
console.log(2 ** 0.5);  // 1.4142135623730951
```
If an operand is NaN, so is the result.
```
console.log(2 + NaN);  // NaN
```

Combined assignment operators

Similar to Java, C++ and many other programming languages, you have combined assignment operators:

let counter = 1;
counter += 10;
console.log(counter);  // 11
console.log((counter -= 2));  // 9

Similar to Java, C++ and many other programming languages, you have increment and decrement operators:

let counter = 1;
console.log(counter++);  // 1
console.log(counter);  // 2
console.log(++counter);  // 3
console.log(--counter);  // 2

Type coercion is another term for type conversion. It is the term the JavaScript community uses more often.

Let’s see what happens when we mix types in arithmetic operations.

console.log("3" - 2);  // ?

The output is 1. The non-number operand is converted to a number.

Now, what about this?

console.log("3" + 2);  // ?

The output is 32. Why? Here, the + operator concatenates strings: the non-string operand is converted to a string.