"Cindy Wang" wrote:
Could someone tell me what is wrong with my function here
"=SUM(IF(ISERROR(E30:E48), " ", E30:E48))"? I t returns
"#VALUE!".

I presume you want the sum of all cells that do not contain an error.

Your formula is correct. But you just need to "array enter" it. That is,
press ctrl+shift+Enter instead of just Enter.

With the normal-entered formula already in the cell, select the cell, press
F2, then press ctrl+shift+Enter instead of just Enter.

An array-entered formula will appear in the Formula Bar surrounded by curly
braces, i.e. {=SUM(...)}. You cannot type the curly braces yourself. That
is just how Excel differentiates an array-entered formula from a
normal-entered formula.

PS: Get in the habit of typing the null string ("") instead of a string
with one space (" "). That will help you when you want to test if a cell
__appears__ blank.