A mathematician and his wife leave the hotel

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…