text: 'use strict';
  
  /*
   * Create a `sub` function that takes 2 numbers as arguments and substract them
   *
   * @notions Primitive and Operators, Functions
   */
  
  // Your code:
  const sub = (num1, num2) => num1 - num2;
  
  //* Begin of tests
  const assert = require('assert');
  const rand = Math.random();
  
  assert.strictEqual(typeof sub, 'function');
  assert.strictEqual(sub.length, 2);
  assert.strictEqual(sub(2, 2), 0);
  assert.strictEqual(sub(-2, 2), -4);
  assert.strictEqual(sub(rand, rand), rand - rand);
  // End of tests */