Sum columns with null values in oracle

Question

I want to add two numbers together but when one of those numbers is null then the result is null. Is there a way around this. I could simply do it in the code but I would

Answer 1

select type, craft, sum(NVL(regular, 0) + NVL(overtime, 0)) as total_hours
from hours_t
group by type, craft
order by type, craft