This one's a few keystrokes shorter:

=IF(ISNUMBER(A1),LOOKUP(A1,{0;11;21;31},{500;600;7 00;""}),"")

Returns a blank "" if A1 30.

Biff

"Biff" wrote in message
...
Hi!

One way:

=IF(ISNUMBER(A1),IF(A1<=10,500,IF(A1<=20,600,IF(A1 <=30,700,"Not
defined"))),"")

You haven't defined what to do if A1 30.

Biff

"Saul" wrote in message
...
Please help with how to write this formula.

If A1 <= 10 then 500
If A1 10 and <= 20 then 600
If A1 20 and <= 30 then 700

Thanks in advance!