Tag Archives: prime

Number of primes below 1000

Do not expect a SQL answer there. My daughter (9) came from school with this question, and I suspect the expected homework was to google for an answer. I am pretty schocked of such practice, teacher encouraging google to do your homework are clearly not from my generation…

Ok, back to the rules, pen and paper. We write down all numbers from 1 to 1000, we start graying out the 1, then the 4,6,8,10,12,… Then the 9 15 21 27 … Then the 25, 35, 55, … Then 7, 49, 77, … And so on.

After having grayed out 1 one, 499 twos, 166 threes, 66 fives, 37 sevens, 20 elevens, 16 thirteens, 10 seventeens, 8 nineteens, 6 twentythrees, 2 twentynines and 1 thirtyone, we counted the remaining numbers and got to the solution. We used the calculator, to gray out numbers like 23*43. But for sure no google there.

I had a similar feeling when my boy teacher ask my boy to look for a description of some exotic butterfly on wikipedia. Is this all what new generations kids can do? Search on google?

Back to google, I once asked in an interview to a young candidate : “How would you speed up a cursor for loop that increases the salary of the employees by 10% ?”. Answer : “I would search on google”.

Not worth mentioning all my traumatic experiences with IT specialists who advise to turn on some tuning magic they found on google to solve their own performance issue with poorly written code.

Using google is good. But do your homework kids :-)