To count the number of cells on a weekday, you can use the SUMPRODUCT and WEEKDAY functions.

**Example:** You are working with a worksheet with the first name in column A, the last name in column B, the date of appointment in column C, and weekdays in column D.

**Question: How many appointments are on Friday?**

=SUMPRODUCT(--(WEEKDAY(C2:C12)=6))

=SUMPRODUCT((WEEKDAY(C2:C12)=6)*1)

The result returns 3, so three appointments are on Friday.

**Explanation: **

- Step 1: WEEKDAY(C2:C12): The result returns the day of the week for each date;
- Step 2: (WEEKDAY(C2:C12)=6): The result returns TRUE if the date is a Friday, or FALSE if not;
- Step 3: The hyphen (or times one) converts TRUE into one and FALSE into zero;
- Step 4: The SUMPRODUCT function returns the sum of the products of the new array.

**Notes: The SUMPRODUCT function**

The SUMPRODUCT function adds all the multiplication results for all arrays.

**Formula:**

=SUMPRODUCT(array1, [array2], …)

**Explanations:**

– Array1 is required; the first array is to multiply and add.

– Array2 is optional; the second array is to multiply and add.