You may have experience working with formulas that contain only one operator, such as 7+9. More complex formulas can contain several mathematical operators, such as 5+2*8. When there's more than one operation in a formula, the order of operations tells Excel which operation to calculate first. To write formulas that will give you the correct answer, you'll need to understand the order of operations.
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Watch the video below to learn more about complex formulas.
Excel calculates formulas based on the following order of operations:
A mnemonic that can help you remember the order is PEMDAS, or Please Excuse My Dear Aunt Sally.
Click the arrows in the slideshow below to learn how the order of operations is used to calculate formulas in Excel.
In the example below, we'll demonstrate how Excel uses the order of operations to solve a more complex formula. Here, we want to calculate the cost of sales tax for a catering invoice. To do this, we'll write our formula as =(D3+D4+D5)*0.075 in cell D6. This formula will add the prices of our items, then multiply that value by the 7.5% tax rate (which is written as 0.075) to calculate the answer.
Excel follows the order of operations and first adds the values inside the parentheses: (45.80+68.70+159.60) = 274.10. It then multiplies that value by the tax rate: 274.10*0.075. The result will show that the sales tax is $20.56.
It's especially important to follow the order of operations when creating a formula. Otherwise, Excel won't calculate the results accurately. In our example, if the parentheses are not included, the multiplication is calculated first and the result is incorrect. Parentheses are often the best way to define which calculations will be performed first in Excel.
In the example below, we'll use cell references along with numerical values to create a complex formula that will calculate the subtotal for a catering invoice. The formula will calculate the cost of each menu item first, then add these values.
You can add parentheses to any equation to make it easier to read. While it won't change the result of the formula in this example, we could enclose the multiplication operations within parentheses to clarify that they will be calculated before the addition.
Excel will not always tell you if your formula contains an error, so it's up to you to check all of your formulas. To learn how to do this, you can read the Double-Check Your Formulas lesson from our Excel Formulas tutorial.
For this challenge, you are going to work with another invoice like the one in our example. In the invoice, you will find the amount of tax for the order, the order's total, and the order's total if you were given a 10% discount.