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Introduction to JavaScript

Arithmetic Operators

Basic arithmetic often comes in handy when programming.

An *operator* is a character that performs a task in our code. JavaScript has several built-in in *arithmetic operators*, that allow us to perform mathematical calculations on numbers. These include the following operators and their corresponding symbols:

- Add:
`+`

- Subtract:
`-`

- Multiply:
`*`

- Divide:
`/`

- Remainder:
`%`

The first four work how you might guess:

```
console.log(3 + 4); // Prints 7
console.log(5 - 1); // Prints 4
console.log(4 * 2); // Prints 8
console.log(9 / 3); // Prints 3
```

Note that when we `console.log()`

the computer will evaluate the expression inside the parentheses and print that result to the console. If we wanted to print the characters `3 + 4`

, we would wrap them in quotes and print them as a string.

```
console.log(11 % 3); // Prints 2
console.log(12 % 3); // Prints 0
```

The remainder operator, sometimes called *modulo*, returns the number that remains after the right-hand number divides into the left-hand number as many times as it evenly can: `11 % 3`

equals 2 because 3 fits into 11 three times, leaving 2 as the remainder.

Inside of a `console.log()`

, add `3.5`

to your age.

This is the age you’ll be when we start sending people to live on Mars.

On a new line write another `console.log()`

. Inside the parentheses, take the current year and subtract `1969`

.

The answer is how many years it’s been since the 1969 moon landing.

Create another `console.log()`

. Inside the parentheses divide `65`

by `240`

.

Create one last `console.log()`

. Inside the parentheses, multiply `0.2708`

by `100`

.

That’s the percent of the sun that is made up of helium. Assuming we could stand on the sun, we’d all sound like chipmunks!