I can't get SUMIF to add the values in a range. I tried:
=SUMIF(B3:B7,"Check",C3:E7)
But it doesn't add all the values in the range C3:E7. It adds only some of
them.

I can make it work by listing each column range to be added separately, like
this:
=SUMIF(B3:B7,"Check",C3:C7)+SUMIF(B3:B7,"Check",D3 :D7)+SUMIF(B3:B7,"Check",E3:E7)

But it's a major pain to enter that whole thing each time.

Any idea why it won't add a range?