关于delphi 判断有关问题

关于delphi 判断问题？
我以前在VB里是这样写的~！
If (Text8.Text = "6.5" Or Text8.Text = "8" Or Text8.Text = "10" Or Text8.Text = "12") And (Label22.Caption >= -7 And Label22.Caption <= 7) Then
Label24 = "达到要求"
Label35 = "合格"

在delphi里
if (edit16.Text='6.5' or edit16.Text='8' or edit16.Text='10' or edit16.Text='12') and (label54.Caption >= '-7' and label54.Caption <= '7') then
label58.Caption:='达到要求'
label59.Caption:='合格'

为什么在label54.Caption <= '7' 位置错误？提示：Operator not applicable to this aperand type 

请高手指点？我应该怎么写这段？

[解决办法]

Delphi(Pascal) code

if ((StrToInt(edit16.Text) in [8,10,12]) or (edit16.Text='6.5')) and ((StrToInt(label54.Caption) >= -7) and (strtoint(label54.Caption) <= 7)) thenbegin  label58.Caption:='达到要求';  label59.Caption:='合格';end;