JavaScript basics arithmetic operators

29 August, 2021 — 4 minute read
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Doing math in JavaScript is a prevalent task. We often want to perform some sort of calculation on one or two numbers.

This is where arithmetic operators come in! Let's see which ones we can use in JavaScript:

Let's have a more detailed view of each of these arithmetic operators in JavaScript.

This can be used to add two numbers, an example:

const a = 5 + 2; // 7
const b = a + 3; // 10

However, be aware the plus sign is also used to combine strings, so doing something like this might surprise you:

const a = '3' + 3; // 33

This happens because it will take the first three as a string and place the number behind it.

This is a super handy operator to quickly increment a number, be aware it has two implementations that can return different results.

In the most basic form it's used like so:

let a = 1;
a++; // 1
console.log(a); // 2

Not that the actual operator does not yet return the new value directly. We can change that behavior by putting the ++ before it.

let a = 1;
++a; // 2
console.log(a); // 2

However, you rarely want to use the value directly.

As we can do addition, we can also subtract two numbers:

const a = 4 - 2; // 2

Weird enough, this will subtract from a string!

const a = '5' - 2; // 3

Or we can decrement a value.

let a = 5;
a--; // 5
console.log(a); // 4

This is used to multiply two numbers.

const a = 2 * 5; // 10

This is a short-hand way to use the Math.pow() function.

It will raise the first number to the power of the second.

const a = 5 ** 3; // 125

Which is the exact same as:

const a = Math.pow(5, 3); // 125

The division is used to divide two numbers.

const a = 10 / 2; // 5

The modulus operator is also known to get the remainder of a division operation.

const a = 10 % 2; // 0
const b = 10 % 3; // 1

Meaning with the first division, we don't have any number left. For the second one, we will keep the number 1 as a left-over.

And with that, we reached the end of the article. I hope you have a solid understanding of JavaScript arithmetic operators.

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