==IFERROR(value,value_if_error)
=IFERROR(A2/B2, "Error in calculation")
returns 6 if A2=210 and B2=35 because A2/B2 = 6 is not an error.
=IFERROR(A3/B3, "Error in calculation")
returns "Error in calculation" if A3=55 and B3=0 because division by zero throws an error.
=IFERROR(A4/B4, "Error in calculation")
returns 0 if if A4="" and B2=23 because there is no error and "" is interpreted as 0.
If there is an error in a formula, the IFERROR function will return a specified value. Otherwise, it will return the result of the formula.
=IFERROR(A1/A2, "Error")