SUMPRODUCT(...)

Category: Math and trigonometry

Returns the sum of the products of corresponding array components

SUMPRODUCT(array1, [array2], [array3], ...)

Category: Information

Returns TRUE if the value is text

ISTEXT(value)

0

We will use the formula SUMPRODUCT() and ISTEXT() to first check if cells contain text and then sum the corresponding binary array returned using SUMPRODUCT() function.