This happened one day in his childhood when he had an upcoming basic mathematics exam involving addition, subtraction, place value identification, division etc... Being a sincere student he had been preparing hard for the exam under the expert guidance of his mom. On the morning of the exam, while he was taking stab at a random bunch of problems his mom realized that there were too many problems to solve in such a short time before starting to prepare to go to school. So, she told him "Don't worry about attempting addition, subtraction and place values..you know it very well. Attack the multiplications and division and get them right. That should be enough". And the genius obliged. Feeling confident after the revision, he left for school to conquer the exam.
That evening his mom enquired,"How was the paper?"
As if he was just waiting for his mom the answer the enquiry, he beamed,"The paper was great! I solved all the division and multiplications right!"
Puzzled, the mom asked, "What about the addition, subtraction and place values..?"
"Oh, but why should I even attempt them mom, I know I do them very well. I just attempted the multiplications and divisions. Isn't that what you said?"