JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 493 · 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 = 49;
   let b = 12;
   console.log(a - b);
2. 2.⚡ What does this code print? (Look at the quotes!)
   let x = "3";
   let y = 9;
   console.log(x + y); (a) 39 (b) Error (c) 12
3. 3.⚡ Which JavaScript word writes in the console? (a) alert() (b) for (c) if (d) console.log()
4. 4.⚡ Which JavaScript word makes a new variable? (a) if (b) alert() (c) let (d) for
5. 5.⚡ What number does this code print?
   let a = 6;
   let b = 3;
   console.log(a * b);
6. 6.⚡ Where does console.log() show its output? (a) on the title bar (b) on the printer (c) in the address bar (d) in the console
7. 7.⚡ What does this code print? (Look at the quotes!)
   let x = "2";
   let y = 1;
   console.log(x + y); (a) 21 (b) 3 (c) Error
8. 8.⚡ What number does this code print?
   let a = 49;
   let b = 9;
   console.log(a + b);
9. 9.⚡ Which JavaScript word repeats code? (a) alert() (b) console.log() (c) if (d) for
10. 10.⚡ What number does this code print?
    let runs = 20;
    runs = runs + 17;
    runs = runs - 28;
    console.log(runs);
11. 11.⚡ Which word makes a new variable? (a) put (b) give (c) let (d) make
12. 12.⚡ Which JavaScript word shows a pop-up box? (a) alert() (b) console.log() (c) for (d) if
13. 13.⚡ What number does this code print?
    let a = 35;
    let b = 31;
    console.log(a + b);
14. 14.⚡ What number does this code print?
    let coins = 29;
    coins = coins + 13;
    coins = coins - 8;
    console.log(coins);
15. 15.⚡ What number does this code print?
    let score = 27;
    score = score + 15;
    score = score - 16;
    console.log(score);
16. 16.⚡ What number does this code print?
    let apples = 18;
    apples = apples + 4;
    apples = apples - 7;
    console.log(apples);
17. 17.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 3;
    console.log(x + y); (a) 63 (b) 9 (c) Error
18. 18.⚡ A JavaScript file usually ends with which extension? (a) .jpg (b) .html (c) .js (d) .css
19. 19.⚡ What does JavaScript add to a web page? (a) the page title (b) the domain name (c) actions and changes (d) only colours
20. 20.⚡ What number does this code print?
    let runs = 16;
    runs = runs + 5;
    runs = runs - 6;
    console.log(runs);
21. 21.⚡ What number does this code print?
    let apples = 13;
    apples = apples + 5;
    apples = apples - 18;
    console.log(apples);
22. 22.⚡ Which JavaScript word runs code when true? (a) for (b) console.log() (c) if (d) let
23. 23.⚡ What number does this code print?
    let a = 24;
    let b = 16;
    console.log(a - b);
24. 24.⚡ What number does this code print?
    let a = 6;
    let b = 11;
    console.log(a * b);
25. 25.⚡ What does this code print? (Look at the quotes!)
    let x = "9";
    let y = 1;
    console.log(x + y); (a) 10 (b) 91 (c) Error
26. 26.⚡ What number does this code print?
    let a = 26;
    let b = 22;
    console.log(a + b);
27. 27.⚡ What number does this code print?
    let books = 12;
    books = books + 11;
    books = books - 2;
    console.log(books);
28. 28.⚡ What does this code show?
    let name = "Arjun";
    alert("Welcome, " + name + "!"); (a) Welcome, Arjun! (b) Welcome, name! (c) Arjun (d) name
29. 29.⚡ What number does this code print?
    let a = 53;
    let b = 14;
    console.log(a - b);
30. 30.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 2;
    console.log(x + y); (a) Error (b) 32 (c) 5
31. 31.⚡ What number does this code print?
    let a = 8;
    let b = 3;
    console.log(a * b);
32. 32.⚡ What number does this code print?
    let a = 19;
    let b = 12;
    console.log(a + b);
33. 33.⚡ What number does this code print?
    let marks = 14;
    marks = marks + 10;
    marks = marks - 12;
    console.log(marks);
34. 34.⚡ What number does this code print?
    let runs = 10;
    runs = runs + 2;
    runs = runs - 10;
    console.log(runs);
35. 35.⚡ What does this code print? (Look at the quotes!)
    let x = "2";
    let y = 2;
    console.log(x + y); (a) 4 (b) Error (c) 22
36. 36.⚡ What number does this code print?
    let a = 10;
    let b = 4;
    console.log(a * b);
37. 37.⚡ What number does this code print?
    let score = 23;
    score = score + 6;
    score = score - 15;
    console.log(score);
38. 38.⚡ What does this code show?
    let name = "Aman";
    alert("Hi, " + name + "!"); (a) name (b) Hi, name! (c) Aman (d) Hi, Aman!
39. 39.⚡ What does this code print? (Look at the quotes!)
    let x = "4";
    let y = 9;
    console.log(x + y); (a) 49 (b) 13 (c) Error
40. 40.⚡ What does this code print? (Look at the quotes!)
    let x = "5";
    let y = 1;
    console.log(x + y); (a) 6 (b) Error (c) 51

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