Although Excel can do extremely complex calculations, the majority of what you're likely to do is very basic: add, subtract, multiply, divide, average, etc. And it's also likely that you're only going to want to do this things to a portion of your list...that is, values meeting certain criteria. In this lesson, we're going to describe some very simple, but useful, functions.

SUMIF / SUMIFS / AVERAGEIF

Let's start with one of the more useful (and self-explanatory) functions: SUMIF. We'll use a simple list of purchased goods over the course of a college student's typical week. 

There are a lot of things we could do with this list. To name a few:

Scenario 1: Total expenses for the week - SUM

Scenario 2: Total expenses allocated towards clothing - SUMIF

Scenario 3: Total expenses associated with lunch at McDonald's - SUMIFS

Scenario 4: Average cost of lunch - AVERAGEIF

Scenario 1: SUM()

The first scenario describes the simplest example, where you want to add all of the items in column D to obtain the total cost. Note that you can add many items to the SUM() function by separating them with a comma. If, for example, you wanted to add the line items in rows 3, 5, and 7, you would use =SUM(D3,D5,D7).

SCENARIO 2: SUMIF() 

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Scenario 3: SUMIFS()

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SCENARIO 4: AVERAGEIF()

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