ISBLANK() =ISBLANK(A2) : Test blank cell

ISNUMBER() =ISNUMBER(A2) : Test numeric

ISTEXT() =ISTEXT(A2) : Test text

ISERROR() =ISERROR(A2/B2) : Test any error

ISERR() =ISERR(A2/B2) : Error except #N/A

ISNA() =ISNA(VLOOKUP(...)) : Test #N/A error

TYPE() =TYPE(A2) : Return type code

CELL() =CELL("address",A2) : Info about cell

FORMULATEXT() =FORMULATEXT(A2) : Return formula as text

N() =N(A2) : Convert value to number

T() =T(A2) : Return text or blank

INFO() =INFO("obversion") : system info

ERROR.TYPE() =ERROR.TYPE(A2) : Numeric code of error