Logic Riddles

Question: What word begins with letter H, but add it with W and it becomes another word yet pronounced just the same?

Question: When you're given one, you'll have either two or none?

Question: What are the next 3 words in the sequence: j,f,m,a,m,j,j,a,s_,_, and _?

Question: If a man has 10 birds and he sells them for 80 chicks each, how many chicks does he have?

Question: A farmer has 10 cows, all but six die. How many are left?