Maths class in school, teacher asks little Billy,
"If I give you two cats then another two cats then two more cats how many cats do you have ?
Seven says Billy.
Ok says the teacher, lets try a different way, if I give you two apples then another two apples and then two more apples how many apples do you have ?
Six .
Great says the teacher, why did you answer seven to the cats ?
I already have one at home.