A mathematician and his wife leave the hotel. They are standing in
the street with their luggage. His wife does not trust him,
because he is very absent-minded, so she says:
Wait here and look after the luggage, and I will call a taxi.
She left him mumbling something under his breath.
When she returned a few minutes later, her husband said:
I thought you said we had 10 suitcases, but I only counted to nine.
No, – says his wife. – There are 10.
No, count yourself: zero, one, two, three…
