Removing duplicates in Excel - Cell-by-Cell Formula Trace

Concept Flow

A
1 Name
2 Alice
3 Bob
4 Alice
5 Charlie
6 Bob
7 David

Formula: =UNIQUE(A2:A7)

Output:
B
1 Unique Names
2 Alice
3 Bob
4 Charlie
5 David

We start with a list of names in column A that contains duplicates. The UNIQUE function is applied to the range A2:A7 to remove duplicates and output only unique names in column B.

Formula

=UNIQUE(A2:A7)

This formula takes the range A2:A7 and returns a list of unique names, removing any duplicates and keeping only the first occurrence of each name.

Step-by-Step Trace

Step	Expression	Evaluates To	Explanation
1	A2:A7	["Alice", "Bob", "Alice", "Charlie", "Bob", "David"]	This is the range of names including duplicates.
2	UNIQUE(["Alice", "Bob", "Alice", "Charlie", "Bob", "David"])	["Alice", "Bob", "Charlie", "David"]	UNIQUE removes duplicate names, keeping only the first occurrence.

The final output is a list of unique names without duplicates.

Variable Tracker

Variable	Value
A2:A7	["Alice", "Bob", "Alice", "Charlie", "Bob", "David"]
UNIQUE(A2:A7)	["Alice", "Bob", "Charlie", "David"]

Key Moments

What does the UNIQUE function do?

Which cells are referenced by the formula?

What is the output value in cell B4?

Sheet Trace Quiz - 3 Questions

What does the UNIQUE function do with the list of names?

A Removes duplicate names and keeps only the first occurrence

B Sorts the names alphabetically

C Counts how many times each name appears

D Reverses the order of the names

Key Result

The UNIQUE function in Excel removes duplicate entries from a range and returns only the first occurrence of each unique value.

Transcript

We have a list of names in column A with duplicates. By using the formula =UNIQUE(A2:A7), Excel scans the range A2 to A7 and extracts only unique names. The duplicates are removed, and the unique names are listed starting in cell B2. This helps to clean data by removing repeated entries easily.

Practice

1. What does the Remove Duplicates feature in Excel do?

easy

A. It deletes repeated entries and keeps only unique values.

B. It sorts the data alphabetically.

C. It highlights duplicate cells without removing them.

D. It copies data to another sheet.

Solution

1. Step 1: Understand the purpose of Remove Duplicates

   This feature is designed to clean data by deleting repeated entries.

2. Step 2: Identify what remains after using Remove Duplicates

   Only unique values remain in the list after duplicates are removed.

3. Final Answer:

   It deletes repeated entries and keeps only unique values. -> Option A

4. Quick Check:

   Remove Duplicates = Keeps unique values [OK]

Hint: Remove Duplicates deletes repeats, leaving unique values only [OK]

Common Mistakes:

• Thinking it only highlights duplicates
• Confusing it with sorting
• Assuming it copies data instead of removing duplicates

2. Which of these is the correct way to start removing duplicates in Excel?

easy

A. Go to the Data tab and click Remove Duplicates.

B. Go to the Home tab and click Sort.

C. Right-click a cell and select Insert Comment.

D. Use the Formulas tab and select Calculate Now.

Solution

1. Step 1: Locate the Remove Duplicates feature

   It is found under the Data tab in Excel's ribbon menu.

2. Step 2: Confirm the correct action to remove duplicates

   Clicking Remove Duplicates under Data tab starts the process.

3. Final Answer:

   Go to the Data tab and click Remove Duplicates. -> Option A

4. Quick Check:

   Remove Duplicates is under Data tab [OK]

Hint: Find Remove Duplicates under Data tab, not Home or Formulas [OK]

Common Mistakes:

• Looking under Home tab instead of Data
• Confusing Remove Duplicates with Sort
• Trying to remove duplicates via formulas tab

3. You have this list in column A:
Apple
Banana
Apple
Orange
Banana
After using Remove Duplicates on column A, what will the list look like?

medium

A. Apple, Banana, Apple, Orange, Banana

B. Apple, Banana, Orange

C. Orange, Banana, Apple

D. Apple, Orange

Solution

1. Step 1: Identify duplicates in the list

   The list has Apple twice and Banana twice.

2. Step 2: Remove repeated entries keeping only unique values

   After removal, only one Apple, one Banana, and one Orange remain.

3. Final Answer:

   Apple, Banana, Orange -> Option B

4. Quick Check:

   Duplicates removed = Apple, Banana, Orange [OK]

Hint: Remove duplicates keeps one of each unique item [OK]

Common Mistakes:

• Expecting duplicates to remain
• Thinking order changes randomly
• Removing unique items by mistake

4. You tried to remove duplicates from a table with columns Name and Email, but duplicates still appear. What is the likely mistake?

medium

A. You sorted the table instead of removing duplicates.

B. You used the Undo button after removing duplicates.

C. You only selected one column instead of both before removing duplicates.

D. You applied Remove Duplicates on a blank sheet.

Solution

1. Step 1: Understand how Remove Duplicates works with multiple columns

   It checks duplicates based on selected columns only.

2. Step 2: Identify the mistake of selecting only one column

   If only one column is selected, duplicates in other columns remain.

3. Final Answer:

   You only selected one column instead of both before removing duplicates. -> Option C

4. Quick Check:

   Select all relevant columns to remove duplicates correctly [OK]

Hint: Select all columns to check before removing duplicates [OK]

Common Mistakes:

• Selecting only one column in multi-column data
• Confusing sorting with removing duplicates
• Trying to remove duplicates on empty data

5. You have a table with columns: Product, Color, Price. You want to remove rows where both Product and Color are duplicates, but keep rows with same Product but different Color. How do you do this?

hard

A. Sort by Price and then remove duplicates.

B. Select all three columns in Remove Duplicates dialog and click OK.

C. Select only Product column in Remove Duplicates dialog and click OK.

D. Select only Product and Color columns in Remove Duplicates dialog and click OK.

Solution

1. Step 1: Identify which columns define duplicates

   Duplicates are rows where both Product and Color match.

2. Step 2: Select only Product and Color columns in Remove Duplicates

   This ensures rows with same Product but different Color stay.

3. Step 3: Confirm that Price is ignored in duplicate check

   Price differences won't affect duplicate removal.

4. Final Answer:

   Select only Product and Color columns in Remove Duplicates dialog and click OK. -> Option D

5. Quick Check:

   Choose columns defining duplicates to remove correctly [OK]

Hint: Select only columns that define duplicates before removing [OK]

Common Mistakes:

• Selecting all columns removes more rows than needed
• Selecting only Product removes rows with different colors
• Sorting does not remove duplicates