['SUM(): This function is used to adds all the values within a cell range.', 'Syntax: sum(cell address : cell address)', 'Example: sum(C1:C3)=15. ... ', 'Example: sum(4,5,6)=15.', 'SUMIF(): ... ', 'Syntax: SUMIF( range,criteria) ... ', 'AVERAGE(): ... ', 'COUNT()']