JavaScript supports standard math operations:
let sum = 10 + 5 // 15
let diff = 10 - 5 // 5
let product = 10 * 5 // 50
let quotient = 10 / 5 // 2
These work with variables too:
let a = 20
let b = 4
console.log(a + b) // 24
console.log(a / b) // 5
Unlike some languages, JavaScript division always returns a decimal if needed. 7 / 2 gives , not .