tag:blogger.com,1999:blog-4227811469912372962.post1743637130579477047..comments2018-05-21T19:53:52.802-07:00Comments on Math off the grid: A quick note on the MathCounts final questionBenjamin Leisnoreply@blogger.comBlogger4125tag:blogger.com,1999:blog-4227811469912372962.post-39847451876721429912016-05-24T20:29:42.724-07:002016-05-24T20:29:42.724-07:00There's the ESPN version: http://espn.go.com/w...There's the ESPN version: http://espn.go.com/watchespn/player/_/id/2810794/ which seemed pretty good. Its around 1:21 into the stream.<br /><br />I was surprised how quickly my kids reached the insight here as well. I'd emphasize how did he save himself doing all the work of the long division. <br /><br />Benjamin Leishttps://www.blogger.com/profile/10974191081762367425noreply@blogger.comtag:blogger.com,1999:blog-4227811469912372962.post-30679098089091900862016-05-24T20:00:54.690-07:002016-05-24T20:00:54.690-07:00Is there a video that shows the last question? Thi...Is there a video that shows the last question? This is the best I could find (<a href="https://www.youtube.com/watch?v=-SOypci5nEU" rel="nofollow">final w/o final question</a>).<br /><br />My plan is to pose the question to my kids and see how they work through it. I'd like to show the video, so we can see how long it took Wan. Then, go back and see if we can figure out other strategies that might be very fast.<br /><br />Maybe a dangerous game, since I don't want to create the impression that speed is important. What I'm going for is an interest in looking for a sharper insight and desire to see the critical element of the problem.<br /><br />In the Beast Academy books, there is a character (Max) who solves problems very quickly in math competitions. We had a lot of fun talking through a relay set-up where a team has a chain of questions with the answer from one used as a key piece of data in the subsequent question. Max figures out the answer to his question without needing the input data. I'd love to find more relay examples and explore more cases where it is possible to skip ahead like that.Joshua Greenehttps://www.blogger.com/profile/11702319994021721608noreply@blogger.comtag:blogger.com,1999:blog-4227811469912372962.post-46549767757571387492016-05-19T11:10:08.432-07:002016-05-19T11:10:08.432-07:00I like that idea. Its a good followup with the foc...I like that idea. Its a good followup with the focus on terms containing fives in the sum.<br /><br />Btw: I still find it amazing that I can do things like this trivially nowadays vs even 10-15 years ago:<br /><br />>> import math<br />>>> math.factorial(30)<br />265252859812191058636308480000000L<br />>>> <br /><br />Benjamin Leishttps://www.blogger.com/profile/10974191081762367425noreply@blogger.comtag:blogger.com,1999:blog-4227811469912372962.post-80517286131302331152016-05-18T18:33:56.693-07:002016-05-18T18:33:56.693-07:00Similarly: Since 8 divides evenly into 200, it als...Similarly: Since 8 divides evenly into 200, it also divides evenly into 1000. Then 32 divides evenly into 4000, so also 100000, etc.<br /><br />Wen probably had the answer faster than 7 seconds, but was checking.<br /><br />Related question: how many zeros at the end of 30!?Five Triangleshttps://www.blogger.com/profile/12846752710456413605noreply@blogger.com