Get the Difference between Two Numbers in JavaScript

Borislav Hadzhiev

Last updated: Jan 6, 2023

Reading timeยท2 min

**To get the difference between two numbers, subtract the first number from the
second and pass the result to the Math.abs() method.**

**The Math.abs() method returns the absolute value of a number.**

index.js

`function getDifference(a, b) { return Math.abs(a - b); } console.log(getDifference(10, 15)); // ๐๏ธ 5 console.log(getDifference(15, 10)); // ๐๏ธ 5 console.log(getDifference(-10, 10)); // ๐๏ธ 20`

The Math.abs() method returns the absolute value of a number.

In other words, it returns the number's distance from zero.

Here are some examples:

index.js

`console.log(Math.abs(-3)); // ๐๏ธ 3 console.log(Math.abs(-3.5)); // ๐๏ธ 3.5 console.log(Math.abs(-0)); // ๐๏ธ 0 console.log(Math.abs(3.5)); // ๐๏ธ 3.5 console.log(Math.abs('-3.5')); // ๐๏ธ 3.5`

The `Math.abs()`

method returns the provided number if it's positive or zero and
the negation of the number if it's negative.

The difference between the numbers is always going to be a positive number, so the

`Math.abs()`

method is perfect for this use case.An alternative approach is to use an `if`

statement.

`if`

statementThis is a two-step process:

- Use an
`if`

statement to check which number is greater. - Subtract the lower number from the greater number.

index.js

`function getDifference(a, b) { if (a > b) { return a - b; } return b - a; } console.log(getDifference(10, 15)); // ๐๏ธ 5 console.log(getDifference(15, 10)); // ๐๏ธ 5 console.log(getDifference(-10, 10)); // ๐๏ธ 20`

The `if`

statement checks if the first number is greater than the second.

If the condition is met, we subtract the lower number from the greater and return the result.

Otherwise, we know that the numbers are equal or the second number is greater, so we do the inverse.

This is a bit more readable than using the

`Math.abs()`

method because the method is very rarely used and not many developers are familiar with it.The code sample could also be shortened by using a ternary operator.

This is a two-step process:

- Use the ternary operator to determine which number is greater.
- Subtract the lower number from the greater number and return the result.

index.js

`const a = 10; const b = -20; const difference = a > b ? a - b : b - a; console.log(difference); // ๐๏ธ 30`

The ternary operator is very similar to an `if/else`

statement.

If the expression to the left of the question mark is truthy, the operator returns the value to the left of the colon, otherwise, the value to the right of the colon is returned.

If you have to do this often, define a reusable function.

index.js

`function getDifference(a, b) { return a > b ? a - b : b - a; } console.log(getDifference(10, 15)); // ๐๏ธ 5 console.log(getDifference(15, 10)); // ๐๏ธ 5 console.log(getDifference(-10, 10)); // ๐๏ธ 20`

The `getDifference`

function takes 2 numbers as parameters and returns the
difference between the numbers.

You can learn more about the related topics by checking out the following tutorials: