The LET function in Excel is a powerful tool that allows you to assign names to calculations or expressions within a formula. This helps to simplify complex formulas by allowing you to reuse expressions multiple times without recalculating them, which improves performance and readability. The LET function is particularly useful when dealing with complex nested formulas or when you want to break down a long formula into more manageable parts.
Syntax
| Formula | Description |
|---|---|
| =LET(name1, value1, [name2, value2, ...], calculation) | Assigns names to the values or expressions and uses them in a calculation. |
- name1, value1: The first name and its corresponding value or expression.
- [name2, value2, ...]: Additional names and their corresponding values or expressions (optional).
- calculation: The final calculation or expression that uses the names defined.
Example
Let's consider an example where we need to calculate the total sales revenue, including a 5% sales tax, for a product. The price per unit is $50, and the number of units sold is 120. We will use the LET function to define the total sales without tax and the tax amount, and then calculate the final revenue.
| Input | Value |
|---|---|
| Price per Unit | $50 |
| Units Sold | 120 |
| Sales Tax Rate | 5% |
To calculate the total sales revenue including tax, use the following formula:
=LET(totalSales, 50*120, taxAmount, totalSales*0.05, totalSales + taxAmount)In this example, totalSales is defined as the product of the price per unit and the number of units sold, and taxAmount is calculated based on the sales tax rate. The final revenue is then the sum of totalSales and taxAmount.
Practice Exercise 1
Task: Use the LET function to calculate the average score of a student across four subjects and determine if the student has passed. The passing score is 60. The scores are as follows:
Hint: Define the total score and average score using the LET function, and then use a logical test to check if the student has passed.
Practice Exercise 2
Task: Use the LET function to calculate the compound interest earned on an investment. The principal amount is $5,000, the annual interest rate is 4%, and the investment is held for 3 years. The interest is compounded annually.
Hint: Use the LET function to define intermediate calculations, such as the amount after one year, two years, and three years, before calculating the total compound interest.
Solution for Exercise 1:
=LET(totalScore, SUM(B2:B5), averageScore, AVERAGE(B2:B5), IF(averageScore>=60, "Pass", "Fail"))Explanation: This formula calculates the total score and average score using the LET function. It then checks if the average score is 60 or above to determine if the student has passed.
Solution for Exercise 2:
=LET(P, 5000, r, 0.04, n, 3, A, P*(1+r)^n, A-P)Explanation: This formula uses the LET function to calculate the compound interest. The intermediate steps calculate the amount after 3 years, and the difference between this amount and the principal gives the compound interest earned.