Basic arithmetic in DAX in Power BI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add two columns in a DAX measure.

Power BI

Total Sales = SUM(Sales[Quantity]) [1] SUM(Sales[Price])

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

A/

B-

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' instead of '+' causes subtraction.

Using '*' or '/' changes the operation to multiplication or division.

The plus sign (+) is used to add two values in DAX.

2fill in blank

medium

Complete the code to calculate the difference between two columns.

Power BI

Difference = SUM(Sales[Revenue]) [1] SUM(Sales[Cost])

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

A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' adds values instead of subtracting.

Using '*' or '/' changes the operation incorrectly.

The minus sign (-) subtracts one value from another in DAX.

3fill in blank

hard

Fix the error in the code to multiply two columns correctly.

Power BI

Total Value = SUM(Sales[Quantity]) [1] SUM(Sales[UnitPrice])

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

A*

B-

C/

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' or '-' instead of '*'.

Using '/' causes division, not multiplication.

The asterisk (*) is used for multiplication in DAX.

4fill in blank

hard

Fill both blanks to calculate the average price per unit.

Power BI

Average Price = SUM(Sales[Revenue]) [1] SUM(Sales[Quantity]) [2] 1

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

A/

B*

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' changes the calculation.

Using '*' instead of '/' causes wrong results.

First, divide total revenue by quantity using '/'. Then subtract 1 using '-'.

5fill in blank

hard

Fill all three blanks to calculate the profit margin percentage.

Power BI

Profit Margin = (SUM(Sales[Revenue]) [1] SUM(Sales[Cost])) [2] SUM(Sales[Revenue]) [3] 100

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

A-

B/

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' changes profit calculation.

Using '*' instead of '/' causes wrong division.

Forgetting to multiply by 100 results in decimal, not percentage.

Subtract cost from revenue with '-'. Divide by revenue with '/'. Multiply by 100 with '*'.

Practice

1. What does the DAX expression Total Sales = SUMX(Sales, Sales[Quantity] * Sales[Price]) calculate?

easy

A. The division of quantity by price

B. The sum of quantity and price

C. The difference between quantity and price

D. The total sales amount by multiplying quantity and price

Solution

1. Step 1: Understand the multiplication operator in DAX

   The asterisk (*) symbol multiplies two numbers or columns in DAX.

2. Step 2: Analyze the expression components

   SUMX(Sales, Sales[Quantity] * Sales[Price]) iterates over Sales table, multiplies Quantity and Price row-by-row, and sums the results.

3. Final Answer:

   The total sales amount by multiplying quantity and price -> Option D

4. Quick Check:

   Quantity * Price = Total Sales [OK]

Hint: Multiply quantity and price to get total sales [OK]

Common Mistakes:

• Confusing multiplication with addition
• Using division instead of multiplication
• Ignoring the column context in calculation

2. Which of the following is the correct syntax to create a new measure that subtracts Discount from TotalPrice in DAX?

easy

A. NewMeasure = TotalPrice + Discount

B. NewMeasure := TotalPrice - Discount

C. NewMeasure = TotalPrice - Discount

D. NewMeasure - TotalPrice - Discount

Solution

1. Step 1: Recall the correct assignment operator in DAX

   DAX uses the equals sign (=) to assign expressions to measures.

2. Step 2: Check the arithmetic operator for subtraction

   The minus sign (-) subtracts one value from another.

3. Final Answer:

   NewMeasure = TotalPrice - Discount -> Option C

4. Quick Check:

   Use '=' for assignment and '-' for subtraction [OK]

Hint: Use '=' to assign and '-' to subtract in DAX [OK]

Common Mistakes:

• Using ':=' instead of '=' for measure assignment
• Using '+' instead of '-' for subtraction
• Missing the assignment operator

3. Given the DAX measure:
Profit = SUM(Sales[Revenue]) - SUM(Sales[Cost])
and the Sales table has Revenue = 1000 and Cost = 700,
what is the value of Profit?

medium

A. 1700

B. 300

C. 700

D. 1000

Solution

1. Step 1: Calculate the sum of Revenue

   SUM(Sales[Revenue]) = 1000 as given.

2. Step 2: Calculate the sum of Cost and subtract

   SUM(Sales[Cost]) = 700, so Profit = 1000 - 700 = 300.

3. Final Answer:

   300 -> Option B

4. Quick Check:

   Revenue - Cost = 300 [OK]

Hint: Subtract total cost from total revenue to get profit [OK]

Common Mistakes:

• Adding instead of subtracting
• Using individual row values instead of sums
• Confusing Revenue and Cost columns

4. Identify the error in this DAX measure:
NetAmount = SUM(Sales[Amount]) + - SUM(Sales[Discount])

medium

A. No error, the syntax is correct

B. Missing parentheses around SUM functions

C. SUM function cannot be used with columns

D. Incorrect use of '+ -' operators together

Solution

1. Step 1: Analyze the operator usage

   The '+ -' uses unary minus after addition, which is valid in DAX.

2. Step 2: Verify the expression

   SUM(Sales[Amount]) + (-SUM(Sales[Discount])) correctly computes net amount as Amount minus Discount.

3. Final Answer:

   No error, the syntax is correct -> Option A

4. Quick Check:

   SUM(Amount) + -SUM(Discount) = Net Amount [OK]

Hint: '+ -' is valid unary minus for subtraction [OK]

Common Mistakes:

• Thinking '+ -' is invalid syntax
• Assuming parentheses are always required around SUM
• Thinking SUM can't be used on columns

5. You want to create a measure that calculates the average price after applying a 10% discount on the Price column. Which DAX expression correctly applies this?

hard

A. AvgDiscountedPrice = AVERAGEX(Sales, Sales[Price] * 0.9)

B. AvgDiscountedPrice = AVERAGE(Sales[Price] * 0.9)

C. AvgDiscountedPrice = SUM(Sales[Price * 0.9]) * 0.9 / COUNT(Sales[Price])

D. AvgDiscountedPrice = SUM(Sales[Price] * 0.9) / COUNT(Sales[Price])

Solution

1. Step 1: Understand the requirement

   We need the average of prices after applying a 10% discount on each price (row context).

2. Step 2: Analyze each option

   Averaging requires row-by-row computation for expressions: AVERAGEX(Sales, Sales[Price] * 0.9) correctly iterates and averages discounted prices. A, C, and D have syntax errors (aggregate on expression without iterator or invalid column reference).

3. Final Answer:

   AvgDiscountedPrice = AVERAGEX(Sales, Sales[Price] * 0.9) -> Option A

4. Quick Check:

   Use AVERAGEX for average of row expressions [OK]

Hint: Apply discount inside AVERAGEX to get correct result [OK]

Common Mistakes:

• Using AVERAGE on expression without iterator
• Using SUM and COUNT instead of AVERAGEX
• Invalid column references like [Price * 0.9]