How to use the COUNTIF function in Excel

The Excel COUNTIF and COUNTIFS Functions

ExcelでCOUNTIF関数を簡単に使う方法

Microsoft Excel でセルを数える方法 (COUNT、COUNTA、COUNTIF、COUNTIFS 関数)

ExcelでCOUNTIFS関数を使う方法

How to use COUNTIF and COUNTIFS in Microsoft Excel

Solving Excel COUNT Problems with COUNTIFS Function (practice file included)

Using the COUNTIF function across sheets in a workbook

How to Count / COUNTIF Items Across Multiple Worksheets in Excel