There was a one-room schoolhouse in a remote rural area. Periodically a regional supervisor would visit the school to evaluate the performance of its teacher. On one visit the supervisor viewed a unit on the addition of fractions. The teacher wrote on the board, 2/3 + 4/5 = 6/8.  After school that day the supervisor spent a great deal of time ensuring that the teacher understood the correct way to add fractions.

On the next visit to the school the supervisor was dismayed to find the teacher again was using the incorrect method of adding fractions. Confronted later in the day, the teacher replied, “I tried your method, but mine is easier to teach.”