index.js

function add(a, b) {
  return parseInt(a) + parseInt(b);
}
if (!process.argv[2] || !process.argv[3]) {
  console.log('Insufficient number of arguments! Give two numbers please!');
}
else {
  console.log('The sum of', process.argv[2], 'and', process.argv[3],
    'is', add(process.argv[2], process.argv[3]));
}