**Author:**
Michal Szymanski

Examples:

```
var x = 5; // assign the value 5 to x
var y = 2; // assign the value 2 to y
var z = x + y; // assign the value 7 to z (x + y)
```

The **assignment** operator (`=`

) assigns a value to a
variable.

```
var x = 10;
```

The **addition** operator (`+`

) adds numbers:

```
var x = 5;
var y = 2;
var z = x + y; // Result 7
```

The **multiplication** operator (`*`

) multiplies numbers.

```
var x = 5;
var y = 2;
var z = x * y; // Result 10
```

JavaScript Arithmetic Operators

Arithmetic operators are used to perform arithmetic on numbers:

Operator | Description |
---|---|

+ | Addition |

- | Subtraction |

* | Multiplication |

** | Exponentiation (ES6) |

/ | Division |

% | Modulus (Division Remainder) |

++ | Increment |

-- | Decrement |

**Note:** Arithmetic operators are fully described in the JS
Arithmetic chapter.

JavaScript Assignment Operators

Assignment operators assign values to JavaScript variables.

Operator | Example | Same As |
---|---|---|

= | x = y | x = y |

+= | x += y | x = x + y |

-= | x -= y | x = x - y |

*= | x *= y | x = x * y |

/= | x /= y | x = x / y |

%= | x %= y | x = x % y |

The **addition assignment** operator (`+=`

) adds a value to
a variable.

```
var x = 10;
x += 5; // Result 15
```

**Note:** Assignment operators are fully described in the JS
Assignment chapter.

JavaScript String Operators

The `+`

operator can also be used to add (concatenate) strings.

```
var txt1 = "John";
var txt2 = "Doe";
var txt3 = txt1 + " " + txt2; // Result "John Doe"
```

The `+=`

assignment operator can also be used to add (concatenate) strings:

```
var txt1 = "What a very ";
txt1 += "nice day"; // Result "What a very nice day"
```

**Note:** When used on strings, the + operator is called the
concatenation operator.

Adding Strings and Numbers

Adding two numbers, will return the sum, but adding a number and a string will return a string:

```
var x = 5 + 5; // Result 10
var y = "5" + 5; // Result 55
var z = "Hello" + 5; // Result Hello5
```

**Remember:** If you add a number and a string, the result will
be a string!

JavaScript Comparison Operators

Operator | Description |
---|---|

== | equal to |

=== | equal value and equal type |

!= | not equal |

!== | not equal value or not equal type |

> | greater than |

< | less than |

>= | greater than or equal to |

<= | less than or equal to |

? | ternary operator |

**Note:** Comparison operators are fully described in the JS
Comparisons chapter.

JavaScript Logical Operators

Operator | Description |
---|---|

&& | logical and |

|| | logical or |

! | logical not |

**Note:** Logical operators are fully described in the JS
Comparisons chapter.

JavaScript Type Operators

Operator | Description |
---|---|

typeof | Returns the type of a variable |

instanceof | Returns true if an object is an instance of an object type |

**Note:** Type operators are fully described in the JS Type
Conversion chapter.

Exercises - test your knowledge

Exercise 1

Multiply `10`

with `5`

, and alert the result:

```
alert(10 *5);
```

Exercise 2

Divide `10`

by `2`

, and alert the result:

```
alert(10 / 2);
```

Exercise 3

`x = 10`

`y = 5`

Use the correct **assignment operator** that will result in `x`

being `15`

(same as `x = x + y`

).

```
x = 10;
y = 5;
x += y;
```

Exercise 4

`x = 10`

`y = 5`

Use the correct assignment operator that will result in `x`

being `50`

(same as `x = x * y`

).

```
x = 10;
y = 5;
x *= y;
```

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