JavaScript
const avg = (...nums) => nums.reduce((acc, val) => acc + val, 0) / nums.length
Examples
avg(...[1, 2, 3]) // 2
avg(1, 2, 3) // 2
const avg = (...nums) => nums.reduce((acc, val) => acc + val, 0) / nums.length
avg(...[1, 2, 3]) // 2
avg(1, 2, 3) // 2