To count the number of even numbers in a range using the COUNTIF function, you can use the following formula:

1. =COUNTIF(B3:B10,"=EVEN(B3:B10)")

Here's a breakdown of the formula:

- COUNTIF: This is the function that counts the number of cells in a range that meet a certain criteria.
- B3:B10: This is the range of cells that you want to count.
- "=EVEN(B3:B10)": This is the criteria that you want to use to count the even numbers in the range. The EVEN function returns TRUE if the number is even, and FALSE if it's odd. The "=" sign is used to compare the result of the EVEN function to the value "TRUE".

Make sure to enclose the criteria in double quotes and use the equal sign to compare the result of the EVEN function to "TRUE". This will ensure that the COUNTIF function counts only the even numbers in the range.