Surprise using the 'is' operator

[codefire]

I thought the 'is' operator was used to identify identical objects,
whereas the '==' operator checked equality. Well, I got a surprise
here:

IDLE 1.1.3
>>> a = 10
>>> b = a
>>> a is b
True
>>> a == b
True
>>> c = 10
>>> a == c
True
>>> a is c
True
>>>

I was NOT expecting the last statement to return True!

What am I missing?

Thanks
Tony