LAMBDA for custom functions in Excel - Practice Problems & Coding Challenges

Challenge - 5 Problems

📊 Formula Result

intermediate

Output of a simple LAMBDA function

What is the output of this formula when entered in a cell?

=LAMBDA(x, x*3)(5)

Excel

=LAMBDA(x, x*3)(5)

A 8

B 5

C 15

D Error

💡 Hint

Think about what the LAMBDA function does with the input 5 and the formula x*3.

The LAMBDA function takes the input 5 as x and multiplies it by 3, resulting in 15.

❓ Function Choice

intermediate

Choose the correct LAMBDA to calculate area of a rectangle

Which LAMBDA formula correctly calculates the area of a rectangle given length and width?

A =LAMBDA(length, width, length+width)

B =LAMBDA(length, width, length/width)

C =LAMBDA(length, width, length-width)

D =LAMBDA(length, width, length*width)

💡 Hint

Area of a rectangle is length multiplied by width.

Option D multiplies length and width, which is the correct formula for area.

🎯 Scenario

advanced

Using LAMBDA with LET to calculate discounted price

You want to create a custom function using LAMBDA and LET to calculate a discounted price.

The discount is 10% of the original price.

Which formula correctly returns the discounted price when you input the original price?

A =LAMBDA(price, LET(discount, price*0.1, price-discount))(100)

B =LAMBDA(price, LET(discount, price+0.1, price-discount))(100)

C =LAMBDA(price, LET(discount, price-0.1, price-discount))(100)

D =LAMBDA(price, LET(discount, price*0.1, price+discount))(100)

💡 Hint

Discount is 10% of price, so multiply price by 0.1.

Option A correctly calculates discount as 10% of price and subtracts it from price.

📊 Formula Result

advanced

Output of recursive LAMBDA function for factorial

What is the output of this formula?

=LAMBDA(n, IF(n<=1, 1, n*FACT(n-1)))(4)

Assume FACT is the name of the LAMBDA function itself (recursive call).

Excel

=LAMBDA(n, IF(n<=1, 1, n*FACT(n-1)))(4)

A 24

B Error

C 10

D 120

💡 Hint

Think about how Excel handles recursive LAMBDA calls and if FACT is defined.

The formula references FACT inside itself but FACT is not defined, so it causes an error.

❓ data_analysis

expert

Analyzing output of a LAMBDA function with multiple parameters

Given the formula:

=LAMBDA(a, b, c, IF(a>b, c, a+b))(3, 5, 10)

What is the output?

Excel

=LAMBDA(a, b, c, IF(a>b, c, a+b))(3, 5, 10)

A 8

B 10

C 15

D Error

💡 Hint

Check the condition a>b and decide which value IF returns.

Since 3 is not greater than 5, the formula returns a+b = 3+5 = 8.