Slashdot Mirror
Seattle Seventh Grader Wins National Math Bee (ap.org)
Edward Wan, a Seattle-based seventh grader has won the national math bee. Wan, who studies at Lakeside Middle School, beat 224 other middle school students nationwide to win the 2016 Raytheon Mathcounts National Competition. From an Associated Press report: Competition officials said in a news release the 13-year-old won the final round by answering the question, "What is the remainder when 999,999,999 is divided by 32?" Wan gave the correct answer of 31 In just under seven seconds.Deadspin reports about the live streaming of the event: Today's Mathcounts national championship for middle-school mathletes aired on ESPN3, and it was definitely the best live sports anyone could be watching at 10 a.m. on a Monday morning. We couldn't agree more.
Maths is about understanding something the right way. And I'm guessing this kid did not take the seven seconds to do anything complicated. He just factored 32. i.e. 2^5. Then noticed that 999,999,999 + 1 = 1,000,000,000 = 10^10 = 2^10 * 5*10 which clearly contains a factor of 2^5. So 32 goes into 1,000,000,000. So the remainder after division of 999,999,999 by 32 is 31. I think you need about 2 seconds for that once you realise the correct way to think about it. So he took 5 seconds to work out what he should do. Quick kid!
Hey, great way to dispel those stereotypes, Wan!!! Keep it up!
I've abandoned my search for truth; now I'm just looking for some useful delusions.
10^n is evenly divisible by 2^n
Therefore 999,999,999 = 10^9-1. Therefore the remainder is -1 mod 32 which = 31.
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Arithmetic. Americans seem unable to tell the difference
Nope. Three problems:
(1) Arithmetic is a PART of mathematics.
(2) Even if you want to insist it's not, the Mathcounts competition includes all sorts of stuff including basic geometry, basic algebra, probability, combinatorics, basic number theory, etc. NOT just arithmetic.
(3) If you think this kid solved that problem by basic "arithmetic" like division in 7 seconds, you're crazy. It requires an understanding of basic divisibility theory (i.e., part of number theory) to see certain patterns. For example, most kids know that you can determined divisibility by 2 by looking at last digit (even or odd). Some might realize that you can determine divisibility by 4 by looking at last TWO digits.
In this case, divisibility requires looking at last FIVE digits. (This requires generalizability of divisibility rules, usually something not taught directly to middle school kids.) Given that adding one produces a number with five zeroes at the end, that number would be divisible by 32, hence this number would have a remainder of 31.
Frankly, I'm surprised it took kids at this level 7 seconds to jump in with such a simple problem.
Prakash Kumar Badalababoom.
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
When you get to the 999,999,999/13 part ...
It is 999,999,999/32. The 13 is his age. The problem is not so hard. 1,000,000,000 is 10^9 = 2^9*5^9, and 32=2^5, so obviously 1,000,000,000 is evenly divisible by 32, so one less is going to have a remainder of 31. Duh.
I don't know much about the Math Bee, but I coach kids for the Math Olympiad, and we do a lot of drills to break numbers down into prime factors, and rapidly compute powers of two. Solving a problem like this in seven seconds is impressive, but not uncommon for a kid that has been trained.
That winning team includes three Asian names, and a head coach and assistant coach each with an Asian name. I don't think that the team is winning because educational standards went up.