[NumLock]

потому что:

Delphi syntax:

function TryStrToFloat(const S: string; out Value: Extended): Boolean; overload;

function TryStrToFloat(const S: string; out Value: Double): Boolean; overload;
function TryStrToFloat(const S: string; out Value: Single): Boolean; overload;

function TryStrToFloat(const S: string; out Value: Extended; const FormatSettings: TFormatSettings): Boolean; overload;

function TryStrToFloat(const S: string; out Value: Double; const FormatSettings: TFormatSettings): Boolean; overload;
function TryStrToFloat(const S: string; out Value: Single; const FormatSettings: TFormatSettings): Boolean; overload;

нет Real