What is referred to by '400 200 100 50'?

Based on the clue '40 kids ages 8 15 tried to live without their pare...', what is the answer? Based on the clue '40 years after a famous incident he was awarded a ...', what is the answer? Based on the clue '40 years ago certain persons went up to laputaandc...', what is the answer? Based on the clue '40 years later julie newmar is still best remembe...', what is the answer? Based on the clue '400 bc i will use treatment to help the sick accor...', what is the answer? Based on the clue '400 meter star cathy freeman is the first of these...', what is the answer? Based on the clue '400 year old pont neuf is the oldest of 30 of thes...', what is the answer? What is associated with: 4000 years ago the first needles used in this chinese medical procedure were made out of stone…