worksheet function

[Kelly]

If B:B contains other numbers such as 404 and 405 could I
have c:c sum if B:B= 402 and 403 while A:A =312?

 

[Ragdyer]

Try this:

=SUMPRODUCT((A1:A65000=312)*((B1:B65000=402)+(B1:B65000=403))*C1:C65000)