Why variables are needed in Javascript - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to store the number 10 in a variable named score.

Javascript

let score = [1];

Drag options to blanks, or click blank then click option'

A'score'

Bten

Cscore

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Putting quotes around 10 makes it a string, not a number.

Using the variable name instead of a value.

We use let score = 10; to store the number 10 in the variable score.

2fill in blank

medium

Complete the code to change the value of the variable score to 20.

Javascript

score [1] 20;

Drag options to blanks, or click blank then click option'

A=

B===

C==

Dequals

Attempts:

3 left

💡 Hint

Common Mistakes

Using == or === instead of = causes comparison, not assignment.

Writing 'equals' is not valid JavaScript syntax.

Use = to assign a new value to a variable.

3fill in blank

hard

Fix the error in the code to declare a variable named name with the value 'Alice'.

Javascript

let [1] = 'Alice';

Drag options to blanks, or click blank then click option'

A1name

BName

Cname

Dna me

Attempts:

3 left

💡 Hint

Common Mistakes

Starting variable names with numbers.

Using spaces inside variable names.

Variable names cannot start with a number or contain spaces. name is a valid variable name.

4fill in blank

hard

Fill both blanks to create a variable that stores the sum of 5 and 3.

Javascript

let total = [1] [2] 3;

Drag options to blanks, or click blank then click option'

A5

B+

C-

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using minus or multiplication instead of addition.

Putting the wrong number or symbol in the blanks.

We add 5 and 3 using the plus sign + and store it in total.

5fill in blank

hard

Fill all three blanks to create an object with a variable key and value.

Javascript

let [1] = 'color';
let [2] = 'blue';
let obj = { [[1]]: [2] };

Drag options to blanks, or click blank then click option'

Akey

Bvalue

Ccolor

Dblue

Attempts:

3 left

💡 Hint

Common Mistakes

Using the string 'color' as a variable name directly.

Mixing up variable names and their values.

We create variables key and value to hold strings, then use them to make an object with a key-value pair.