COUNTBLANK

Counts empty cells in a specified range of cells.
Syntax
COUNTBLANK(range)
Range    is the range from which you want to count the blank cells.
Remark
Cells with formulas that return "" (empty text) are also counted. Cells with zero values are not counted.
Example
The example may be easier to understand if you copy it to a blank worksheet.

	A	B
1	Data	Data
2
3	6	=IF(B4<30,"",B4)
4		27
5	4	34

Formula	Description (Result)
=COUNTBLANK(A2:B5)	Counts empty cells in the range above. The formula returns empty text. (4)

SUMIF

Adds the cells specified by a given criteria.
Syntax
SUMIF(range,criteria,sum_range)
Range    is the range of cells you want evaluated.
Criteria    is the criteria in the form of a number, expression, or text that defines which cells will be added. For example, criteria can be expressed as 32, "32", ">32", "apples".
Sum_range    are the actual cells to sum.
Remarks

• The cells in sum_range are summed only if their corresponding cells in range match the criteria.
  
• If sum_range is omitted, the cells in range are summed.
  
• Microsoft Excel provides additional functions that can be used to analyze your data based on a condition. For example, to count the number of occurrences of a string of text or a number within a range of cells, use the COUNTIF function. To have a formula return one of two values based on a condition, such as a sales bonus based on a specified sales amount, use the IF function.
  

Example
The example may be easier to understand if you copy it to a blank worksheet.

	A	B
1	Property Value	Commission
2	100,000	7,000
3	200,000	14,000
4	300,000	21,000
5	400,000	28,000

Formula	Description (Result)
=SUMIF(A2:A5,">160000",B2:B5)	Sum of the commissions for property values over 160000 (63,000)