Grid container in CSS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ layout

intermediate

What is the number of columns in this grid container?

Consider the following CSS code for a grid container. How many columns will the grid have?

CSS

display: grid;
grid-template-columns: repeat(3, 1fr);

A 1

B 2

C 3

D 4

💡 Hint

The repeat function sets how many columns are created.

The property grid-template-columns: repeat(3, 1fr) creates 3 equal columns in the grid container.

❓ selector

intermediate

Which CSS property makes an element a grid container?

You want to turn a

into a grid container. Which CSS property and value should you use?

A display: flex;

B display: block;

C position: grid;

D display: grid;

💡 Hint

The display property controls the layout type of an element.

Setting display: grid; makes the element a grid container, enabling grid layout for its children.

❓ rendering

advanced

What will be the width of each column in this grid container?

Given this CSS, what is the width of each column if the container is 600px wide?

CSS

display: grid;
grid-template-columns: 100px 2fr 1fr;

A 100px, 333.33px, 166.67px

B 100px, 200px, 300px

C 100px, 400px, 100px

D 100px, 250px, 250px

💡 Hint

fr units divide remaining space proportionally after fixed widths.

The first column is fixed 100px. Remaining space is 500px (600-100). 2fr + 1fr = 3fr total. So 2fr = 2/3 * 500 = 333.33px, 1fr = 1/3 * 500 = 166.67px.

❓ accessibility

advanced

Which practice improves accessibility for grid containers?

When using CSS grid for layout, which practice helps screen reader users understand the page structure better?

A Use semantic HTML elements inside the grid container.

B Add tabindex="-1" to all grid items.

C Use only div elements with no ARIA roles.

D Avoid using grid-template-areas.

💡 Hint

Screen readers rely on meaningful HTML tags.

Using semantic elements like

,

,

inside grid containers helps screen readers understand content roles and structure.

🧠 Conceptual

expert

What happens if you set grid-template-columns: auto auto auto; on a grid container with three items of different content widths?

Consider a grid container with three items. The CSS is: grid-template-columns: auto auto auto; What will be the width of each column?

A All columns have equal width regardless of content.

B Each column width matches the widest content in that column.

C Columns shrink to zero width if content is small.

D Columns ignore content size and fill container equally.

💡 Hint

The auto keyword sizes columns based on content.

Using auto for columns means each column's width fits its widest content, so columns can have different widths.

Practice

1. What CSS property do you use to make an element a grid container?

easy

A. grid-template-columns: auto;

B. display: flex;

C. position: grid;

D. display: grid;

Solution

1. Step 1: Understand grid container basics

   To create a grid layout, the container must have display: grid; set.

2. Step 2: Check other options

   display: flex; creates a flexbox, not grid. position: grid; is invalid. grid-template-columns defines columns but does not make container a grid.

3. Final Answer:

   display: grid; -> Option D

4. Quick Check:

   Grid container = display: grid; [OK]

Hint: Grid container always needs display: grid; [OK]

Common Mistakes:

• Using display: flex; instead of grid
• Trying to use position: grid;
• Setting grid-template-columns without display: grid;

2. Which of the following is the correct syntax to create a grid with 3 equal columns?

easy

A. grid-template-columns: 1fr 1fr 1fr;

B. grid-template-columns: 3px;

C. grid-columns: repeat(3, 1fr);

D. grid-template-rows: 1fr 1fr 1fr;

Solution

1. Step 1: Understand grid-template-columns syntax

   The property grid-template-columns defines columns. Using 1fr 1fr 1fr creates 3 equal columns.

2. Step 2: Check other options

   3px is a fixed small width, not equal columns. grid-columns is invalid property. grid-template-rows sets rows, not columns.

3. Final Answer:

   grid-template-columns: 1fr 1fr 1fr; -> Option A

4. Quick Check:

   Equal columns = grid-template-columns: 1fr 1fr 1fr; [OK]

Hint: Use grid-template-columns with 1fr units for equal columns [OK]

Common Mistakes:

• Using grid-columns instead of grid-template-columns
• Confusing rows and columns properties
• Using fixed px values for equal flexible columns

3. Given this CSS:

 .container {
  display: grid;
  grid-template-columns: 100px 200px;
  grid-template-rows: 50px 50px;
}

How many grid cells are created inside .container?

medium

A. 4

B. 2

C. 6

D. 8

Solution

1. Step 1: Calculate columns and rows

   There are 2 columns (100px and 200px) and 2 rows (50px and 50px).

2. Step 2: Multiply columns by rows

   Total grid cells = 2 columns x 2 rows = 4 cells.

3. Final Answer:

   4 -> Option A

4. Quick Check:

   2 columns x 2 rows = 4 cells [OK]

Hint: Multiply number of columns by rows for total grid cells [OK]

Common Mistakes:

• Adding columns and rows instead of multiplying
• Counting only columns or only rows
• Confusing grid cells with grid lines

4. What is wrong with this CSS if the goal is to create a grid container with 3 equal columns?

 .grid {
  display: grid;
  grid-template-columns: repeat(3);
}

medium

A. display: grid; is missing

B. Missing unit for repeat count

C. repeat() requires two arguments: count and size

D. grid-template-columns cannot use repeat()

Solution

1. Step 1: Check repeat() syntax

   The repeat() function needs two arguments: number of times and size, e.g. repeat(3, 1fr).

2. Step 2: Identify the error

   Here, only repeat(3) is given, missing the size argument, so it's invalid.

3. Final Answer:

   repeat() requires two arguments: count and size -> Option C

4. Quick Check:

   repeat() needs count and size [OK]

Hint: repeat() always needs count and size, like repeat(3, 1fr) [OK]

Common Mistakes:

• Using repeat() with only one argument
• Forgetting to specify display: grid;
• Thinking repeat() is invalid in grid-template-columns

5. You want a grid container that has 2 columns: the first column is 150px wide, and the second column fills the remaining space. Which CSS is correct?

hard

A. display: grid; grid-template-columns: 150px auto;

B. display: grid; grid-template-columns: 150px 1fr;

C. display: grid; grid-template-columns: auto 150px;

D. display: grid; grid-template-columns: 1fr 150px;

Solution

1. Step 1: Understand fixed and flexible columns

   150px is fixed width. To fill remaining space, use 1fr which means flexible fraction.

2. Step 2: Check options

   display: grid; grid-template-columns: 150px auto; uses auto which sizes based on content, not remaining space. Options B and D put 150px in wrong column order.

3. Final Answer:

   display: grid; grid-template-columns: 150px 1fr; -> Option B

4. Quick Check:

   Fixed + flexible = 150px 1fr [OK]

Hint: Use 1fr for flexible space after fixed width [OK]

Common Mistakes:

• Using auto instead of 1fr for flexible space
• Swapping column order
• Not setting display: grid;