old_contents: 
  module("About Operators (topics/about_operators.js)");
  
  test("addition", function() {
    var result = 0;
    //starting i at 0, add i to result and increment i by 1 until i is equal to 5
    for (var i = 0; i <= 5; i++) {
      result = result + i;
    }
    equal(__, result, "What is the value of result?");
  });
  
  test("assignment addition", function() {
    var result = 0;
    for (var i = 0; i <=5; i++) {
      //the code below is just like saying result = result + i; but is more concise
      result += i;
    }
    equal(__, result, "What is the value of result?");
  });
  
  test("subtraction", function() {
    var result = 5;
    for (var i = 0; i <= 2; i++) {
      result = result - i;
    }
    equal(__, result, "What is the value of result?");
  });
  
  test("assignment subtraction", function() {
    var result = 5;
    for (var i = 0; i <= 2; i++) {
      result -= i;
    }
    equal(__, result, "What is the value of result?");
  });
  
  //Assignment operators are available for multiplication and division as well
  //let's do one more, the modulo operator, used for showing division remainder
  
  test("modulus", function() {
    var result = 10;
    var x = 5;
    //again this is exactly the same as result = result % x
    result %= x;
    equal(__, result, "What is the value of result?");
  });
  
new_contents: 
  module("About Operators (topics/about_operators.js)");
  
  test("addition", function() {
    var result = 0;
    //starting i at 0, add i to result and increment i by 1 until i is equal to 5
    for (var i = 0; i <= 5; i++) {
      result = result + i;
    }
    equal(15, result, "What is the value of result?");
  });
  
  test("assignment addition", function() {
    var result = 0;
    for (var i = 0; i <=5; i++) {
      //the code below is just like saying result = result + i; but is more concise
      result += i;
    }
    equal(15, result, "What is the value of result?");
  });
  
  test("subtraction", function() {
    var result = 5;
    for (var i = 0; i <= 2; i++) {
      result = result - i;
    }
    equal(2, result, "What is the value of result?");
  });
  
  test("assignment subtraction", function() {
    var result = 5;
    for (var i = 0; i <= 2; i++) {
      result -= i;
    }
    equal(2, result, "What is the value of result?");
  });
  
  //Assignment operators are available for multiplication and division as well
  //let's do one more, the modulo operator, used for showing division remainder
  
  test("modulus", function() {
    var result = 10;
    var x = 5;
    //again this is exactly the same as result = result % x
    result %= x;
    equal(0, result, "What is the value of result?");
  });
  
subject: Complete about_operator