Math

Doing math in javascript is just about as simple as doing math with a pen and paper. The four main operators in javascript are represented as follows

Using the operators is also about as simple as one would imagine it would be

console.log(2 + 2) // This outputs "4"

In most cases, when we want to do math in our javascript programs, it will be with a dynamic value that the user inputs, represented by a variable. Applying what we just learned about variables, let's look at some examples using variables to both hold the numbers and store the result

const number1 = 10
const number2 = 4

const sum = number1 + number2
console.log(sum) // Outputs: 14 c

const difference = number1 - number2
console.log(difference) // Outputs: 6

const product = number1 * number2
console.log(product) // Outputs: 40

const quotient = number1 / number2
console.log(quotient) // Outputs: 2.5

There are two more operators that are quite common: ++ and --. These are shorthand for incrementing or decrementing a variable by 1, which is very useful when doing things like loops (not covered in this lesson)

The lines of code shown in the two examples below are equivalent

let total = 0
total = total + 1
console.log(total) // Outputs 1

let total = 0
total++
console.log(total) // Outputs 1

The same is true for the decrementation operator

let total = 10
total = total - 1
console.log(total) // Outputs 9

let total = 10
total--
console.log(total) // Outputs 9

One final thing to note is that all math done using JavaScript follows the standard order of operations, Where math in parentheses/brackets is executed first, then multiplication and division, then addition and subtraction.