My first is in tea but not in leaf
My second is in teapot and also in teeth
My third is in caddy but not in cosy
My fourth is in cup but not in rosy
My fifth is in herbal and also in health
My sixth is in peppermint and always in wealth
My last is in drink, so what can I be?
I’m there in a classroom, do you listen to me?

A spy satellite circles around the earth in 1.57 hours. Can you tell within 3 seconds how much time it takes until the satellite has made 24 revolutions?

Suppose, you would like to divide the pie from the figure on the right-hand side into eight equal pieces. How often do you minimally have to cut? Every time you put the knife again in the pie counts as an additional cut.