Logic Riddles

Question: What grows when you take from it?

Question: what can go up a chimney down but cant go down a chimney up

Question: What is in the middle of the moon, At the end of an igloo And goes round in loops?

Question: what are the next two letters in this sequence: A, E, F, H, I, K, L, M,

Question: What are the next two letters in the following series and why? WATNTLITFS__