Teen Math

I have a new phrase to add to Webster's dictionary:

teen math /tēn math/ n A branch of mathematics pertaining to household chores, where the whole is inexplicably less than the sum total of its components.
Example: When a mother washes all the dishes before leaving home, and on her return discovers the sink half-full of dishes. Yet, unexplainably, all various and sundry teens claim that they washed all of their own dishes. Thus the sum total , which should be all of the dishes, is inexplicably more than the whole (amount of dishes washed).

But they (the teens) made supper, and one drove me to the doctor's appointment with Ricki, so the pluses far outweighed the minuses. As a result, in spite of "teen math", the teens got a passing grade…….