JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 139 · 40 questions

Code tip (Line by line): let x = 5; makes a variable x holding 5; x = x + 2; changes it to 7. console.log(…) writes in the console; alert(…) shows a pop-up box. Text in quotes + anything = joined text: "5" + 3 → "53".

1. 1.⚡ What number does this code print?
   let a = 15;
   let b = 12;
   console.log(a - b);
2. 2.⚡ What number does this code print?
   let a = 16;
   let b = 36;
   console.log(a + b);
3. 3.⚡ A JavaScript file usually ends with which extension? (a) .html (b) .js (c) .jpg (d) .css
4. 4.⚡ What number does this code print?
   let a = 10;
   let b = 5;
   console.log(a + b);
5. 5.⚡ Which JavaScript word writes in the console? (a) if (b) let (c) alert() (d) console.log()
6. 6.⚡ Where does console.log() show its output? (a) on the printer (b) in the console (c) in the address bar (d) on the title bar
7. 7.⚡ What does this code print? (Look at the quotes!)
   let x = "3";
   let y = 7;
   console.log(x + y); (a) Error (b) 37 (c) 10
8. 8.⚡ What number does this code print?
   let a = 37;
   let b = 38;
   console.log(a + b);
9. 9.⚡ Which JavaScript word repeats code? (a) for (b) if (c) let (d) console.log()
10. 10.⚡ What does this code show?
    let name = "Aman";
    console.log("Hello, " + name + "!"); (a) name (b) Hello, name! (c) Aman (d) Hello, Aman!
11. 11.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 6;
    console.log(x + y); (a) 36 (b) 9 (c) Error
12. 12.⚡ What number does this code print?
    let books = 19;
    books = books + 6;
    books = books - 12;
    console.log(books);
13. 13.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 2;
    console.log(x + y); (a) Error (b) 82 (c) 10
14. 14.⚡ What number does this code print?
    let score = 20;
    score = score + 2;
    score = score - 5;
    console.log(score);
15. 15.⚡ What does alert() show? (a) a picture (b) a pop-up box (c) a table (d) a new tab
16. 16.⚡ What number does this code print?
    let a = 24;
    let b = 5;
    console.log(a - b);
17. 17.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 7;
    console.log(x + y); (a) 87 (b) 15 (c) Error
18. 18.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 1;
    console.log(x + y); (a) 9 (b) Error (c) 81
19. 19.⚡ What does JavaScript add to a web page? (a) only colours (b) the page title (c) actions and changes (d) the domain name
20. 20.⚡ Which JavaScript word shows a pop-up box? (a) let (b) alert() (c) console.log() (d) for
21. 21.⚡ Which JavaScript word runs code when true? (a) if (b) for (c) let (d) alert()
22. 22.⚡ What does this code show?
    let name = "Aman";
    alert("Hello, " + name + "!"); (a) name (b) Aman (c) Hello, Aman! (d) Hello, name!
23. 23.⚡ What number does this code print?
    let apples = 17;
    apples = apples + 11;
    apples = apples - 25;
    console.log(apples);
24. 24.⚡ What number does this code print?
    let runs = 5;
    runs = runs + 3;
    runs = runs - 3;
    console.log(runs);
25. 25.⚡ Which JavaScript word makes a new variable? (a) let (b) console.log() (c) for (d) if
26. 26.⚡ What number does this code print?
    let apples = 26;
    apples = apples + 17;
    apples = apples - 15;
    console.log(apples);
27. 27.⚡ Which tag holds JavaScript in a page? (a) <code> (b) <style> (c) <script> (d) <js>
28. 28.⚡ What number does this code print?
    let a = 4;
    let b = 10;
    console.log(a * b);
29. 29.⚡ What number does this code print?
    let marks = 12;
    marks = marks + 15;
    marks = marks - 21;
    console.log(marks);
30. 30.⚡ What number does this code print?
    let a = 60;
    let b = 22;
    console.log(a + b);
31. 31.⚡ What number does this code print?
    let a = 21;
    let b = 8;
    console.log(a + b);
32. 32.⚡ What does this code show?
    let name = "Aman";
    alert("Welcome, " + name + "!"); (a) Welcome, Aman! (b) name (c) Aman (d) Welcome, name!
33. 33.⚡ What does this code show?
    let name = "Aman";
    alert("Hi, " + name + "!"); (a) Hi, name! (b) Aman (c) name (d) Hi, Aman!
34. 34.⚡ What number does this code print?
    let apples = 29;
    apples = apples + 19;
    apples = apples - 16;
    console.log(apples);
35. 35.⚡ What number does this code print?
    let a = 10;
    let b = 9;
    console.log(a + b);
36. 36.⚡ What does this code show?
    let name = "Meera";
    alert("Hi, " + name + "!"); (a) Meera (b) name (c) Hi, Meera! (d) Hi, name!
37. 37.⚡ What number does this code print?
    let a = 6;
    let b = 4;
    console.log(a * b);
38. 38.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 5;
    console.log(x + y); (a) Error (b) 6 (c) 15
39. 39.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 5;
    console.log(x + y); (a) Error (b) 13 (c) 85
40. 40.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 4;
    console.log(x + y); (a) Error (b) 64 (c) 10

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