Column sizing (col-1 through col-12) in Bootsrap - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does col-6 mean in Bootstrap grid?

It means the column will take up 6 out of 12 parts of the row width, so half the row.

beginner

How many total columns does Bootstrap's grid system have?

Bootstrap's grid system has 12 columns in total.

beginner

What happens if you add three col-4 columns in one row?

They will each take 4 parts, so together they fill the entire 12-column row equally.

intermediate

Can you use col-1 to col-12 classes together in one row?

Yes, you can mix different column sizes as long as their total does not exceed 12.

beginner

What is the visual effect of using col-12 on a column?

The column will stretch across the entire row width, taking all 12 parts.

In Bootstrap, what does col-3 represent?

A A column that takes 6/12 of the row width

B A column that takes 3/12 of the row width

C A column that takes 9/12 of the row width

D A column that takes the full row width

col-3 means the column uses 3 parts out of 12 total parts in the row.

How many col-4 columns fit exactly in one Bootstrap row?

A 3

B 2

C 4

D 6

Three col-4 columns each take 4 parts, totaling 12 parts (4+4+4=12).

What happens if column sizes in a row add up to more than 12?

A Columns wrap to the next line

B Columns shrink automatically

C Columns overlap each other

D The row breaks and shows an error

Bootstrap wraps extra columns to a new line if total exceeds 12.

Which class makes a column take the full width of the row?

A col-1

B col-6

C col-12

D col-4

col-12 means the column uses all 12 parts, filling the row.

Can you mix col-2 and col-10 in the same row?

A No, columns must be the same size

B Yes, but only if they add up to more than 12

C No, only multiples of 3 are allowed

D Yes, if their total is 12 or less

You can mix column sizes as long as their total does not exceed 12.

Explain how Bootstrap's column sizing works using col-1 through col-12 classes.

Think of dividing a pizza into 12 slices.

Describe what happens visually when you use three col-4 columns in one Bootstrap row.

Imagine three equal boxes side by side filling a shelf.

Practice

1. What does the Bootstrap class col-6 mean in a grid layout?

easy

A. The column takes up half the width of the row (6 out of 12 parts).

B. The column takes up 6 pixels width.

C. The column is hidden on screens smaller than 6 inches.

D. The column has 6 columns inside it.

Solution

1. Step 1: Understand Bootstrap grid system

   Bootstrap divides a row into 12 equal parts for layout.

2. Step 2: Interpret col-6

   The class col-6 means the column uses 6 of those 12 parts, which is half the row width.

3. Final Answer:

   The column takes up half the width of the row (6 out of 12 parts). -> Option A

4. Quick Check:

   col-6 means 6/12 width = half [OK]

Hint: Remember: col-# means # out of 12 parts width [OK]

Common Mistakes:

• Thinking col-6 means 6 pixels wide
• Confusing col-6 with number of columns inside
• Assuming col-6 hides the column on small screens

2. Which of the following is the correct way to create a column that takes one quarter of the row width using Bootstrap classes?

easy

A. col-3

B. col-4

C. col-6

D. col-9

Solution

1. Step 1: Calculate quarter width in 12 parts

   One quarter of 12 parts is 12 ÷ 4 = 3 parts.

2. Step 2: Match with Bootstrap class

   The class col-3 means 3 parts width, which is one quarter.

3. Final Answer:

   <code>col-3</code> -> Option A

4. Quick Check:

   3 parts = 1/4 width [OK]

Hint: Divide 12 by desired fraction to find col-# [OK]

Common Mistakes:

• Choosing col-4 which is one third, not quarter
• Confusing col-6 as quarter width
• Picking col-9 which is three quarters

3. Given this HTML snippet:

<div class='row'>
  <div class='col-4'>A</div>
  <div class='col-8'>B</div>
</div>

How will the columns appear on a large screen?

medium

A. Column A takes 4/12 width, Column B takes 8/12 width stacked vertically.

B. Column A and B stack vertically, each full width.

C. Column A takes 1/3 width, Column B takes 2/3 width side by side.

D. Column A takes 8/12 width, Column B takes 4/12 width side by side.

Solution

1. Step 1: Understand col-4 and col-8 widths

   col-4 means 4 parts out of 12 (1/3), col-8 means 8 parts out of 12 (2/3).

2. Step 2: Check layout behavior in Bootstrap

   Columns inside a row appear side by side if total is 12 or less.

3. Final Answer:

   Column A takes 1/3 width, Column B takes 2/3 width side by side. -> Option C

4. Quick Check:

   4 + 8 = 12 parts, side by side [OK]

Hint: Sum col-# classes; if 12 or less, columns sit side by side [OK]

Common Mistakes:

• Thinking columns stack vertically by default
• Mixing up col-4 and col-8 widths
• Assuming col-4 means 1/4 width

4. What is wrong with this Bootstrap column layout?

<div class='row'>
  <div class='col-5'>X</div>
  <div class='col-8'>Y</div>
</div>

medium

A. The classes col-5 and col-8 are invalid in Bootstrap.

B. The columns add up to more than 12, causing layout issues.

C. The columns will stack vertically because col-5 is less than col-6.

D. The row class is missing, so columns won't align.

Solution

1. Step 1: Add column widths

   col-5 means 5 parts, col-8 means 8 parts; total is 5 + 8 = 13 parts.

2. Step 2: Check Bootstrap grid rules

   Columns in a row should add up to 12 or less for proper layout; more than 12 breaks layout.

3. Final Answer:

   The columns add up to more than 12, causing layout issues. -> Option B

4. Quick Check:

   5 + 8 = 13 > 12 breaks layout [OK]

Hint: Sum col-# classes; must be ≤ 12 for correct layout [OK]

Common Mistakes:

• Thinking col-5 or col-8 are invalid classes
• Assuming columns stack because of size difference
• Ignoring total width exceeding 12

5. You want to create a responsive layout with three columns where:
- The first column is 3 parts wide
- The second column is twice as wide as the first
- The third column fills the remaining space
Which Bootstrap classes should you use?

hard

A. col-3, col-5, col-4

B. col-3, col-6, col-4

C. col-2, col-4, col-6

D. col-3, col-6, col-3

Solution

1. Step 1: Assign widths based on conditions

   First column = 3 parts; second column = twice first = 6 parts.

2. Step 2: Calculate remaining space for third column

   Total so far: 3 + 6 = 9 parts; remaining = 12 - 9 = 3 parts.

3. Step 3: Match with Bootstrap classes

   Use col-3, col-6, and col-3 for the three columns respectively.

4. Final Answer:

   <code>col-3</code>, <code>col-6</code>, <code>col-3</code> -> Option D

5. Quick Check:

   3 + 6 + 3 = 12 parts total [OK]

Hint: Double first col width, subtract sum from 12 for last [OK]

Common Mistakes:

• Choosing widths that sum over 12
• Not doubling the first column width correctly
• Assigning third column more than remaining space