a young boy who on many occasions had seen his father refuse to pay his debts even after heated quarrel with those he is indebted to, finds himself in a mathematics class and the topic was SUBTRACTION. See what transpired.
teacher: Emeka, if your dad bought rice at the rate of #250 from a neighbor and paid only #100, how much money is left for him to pay?
Emeka: the answer is nothing sir.

teacher: why did you say so?

Emeka: sir, I have never seen my dad give money to those he is indebted to whenever they come for it. so the answer is zero because my dad will not pay anything.