01

Use {} to destructe individual variables fron module

                 
const { subtract, divide } = require('./math')
console.log(subtract(10,5))
console.log(divide(87,10))

02

In modules like math.js,You can use exports. in modules instead of module.exports

you must use specific path when not using Common Core Modules. You do not need .js

exports.const add = (a,b) => a + b
exports.const subtract = (a,b) => a - b
exports.const multiply = (a,b) => a * b
exports.const divide = (a,b) => a / b