This Scribe shows you how to use the SUMIF function in Google Sheets. It will sum certain values based on a criteria you define. The syntax for SUMIF is as follows:
= sumif(Range, Criteria, Sum_Range)

Select the cell where you want to write your formula

Type "=sumif(A2:A8,A3,C2:C8)" and press [[enter]]

Tip! The criteria can be a cell or a hardcoded value or text string. If you wanted to use a text string for this example, the formula would look like:
= sumif(A2:A8,"Jessie",C2:C8)

Google Sheets is a powerful online tool to help you do quantitative analysis. Learn how to use formulas to manipulate and analyze datasets, such as Google Sheets' COUNTIF and SUMIF functions, among many others.

How to use SUMIF in Google Sheets