## Tutorial

Every variable in JavaScript is casted automatically so any operator between two variables will always give some kind of result.

### The addition operator

The `+`

(addition) operator is used for both addition and concatenation of strings.

For example, adding two variables is easy:

```
var a = 1;
var b = 2;
var c = a + b; // c is now equal to 3
```

The addition operator is used for concatenating strings to strings, strings to numbers, and numbers to strings:

```
var name = "John";
console.log("Hello " + name + "!");
console.log("The meaning of life is " + 42);
console.log(42 + " is the meaning of life");
```

JavaScript behaves differently when you are trying to combine two operands of different types. The default primitive value is a string, so when you try to add a number to a string, JavaScript will transform the number to a string before the concatenation.

```
console.log(1 + "1"); // outputs "11"
```

### Mathematical operators

To subtract, multiply and divide two numbers, use the minus (`-`

), asterisk (`*`

) and slash (`/`

) signs.

```
console.log(3 - 5); // outputs -2
console.log(3 * 5); // outputs 15
console.log(3 / 5); // outputs 0.6
```

### Advanced mathematical operators

JavaScript supports the modulus operator (`%`

) which calculates the remainder of a division operation.

```
console.log(5 % 3); // outputs 2
```

JavaScript also supports combined assignment and operation operators. So, instead of typing `myNumber = myNumber / 2`

, you can type `myNumber /= 2`

. Here is a list of all these operators:

`/=`

`*=`

`-=`

`+=`

`%=`

JavaScript also has a `Math`

module which contains more advanced functions:

`Math.abs`

calculates the absolute value of a number`Math.exp`

calculates**e**to the power of a number`Math.pow(x,y)`

calculates the result of**x**to the power of**y**`Math.floor`

removes the fraction part from a number`Math.random()`

will give a random number`x`

where 0<=x<1

And many more mathematical functions.

## Exercise

In this exercise, you do the following:

- Connect the
`firstName`

and`lastName`

to construct the variable`fullName`

, but with a space (`" "`

) in between the first and last name. - Multiply the variable
`myNumber`

by 2 and put the result in`meaningOfLife`

.

## Tutorial Code

var firstName = “John”; var lastName = “Smith”; var myNumber = 21;

// TODO: change the following code var fullName = null; var meaningOfLife = null;

console.log(“The name is “ + fullName); console.log(“The meaning of life is “ + meaningOfLife);

## Expected Output

The name is John Smith The meaning of life is 42

## Solution

var firstName = “John”; var lastName = “Smith”; var myNumber = 21;

// TODO: change the following code var fullName = firstName + “ “ + lastName; var meaningOfLife = myNumber * 2;

console.log(“The name is “ + fullName); console.log(“The meaning of life is “ + meaningOfLife);