Math Sequence Riddles – It’s never too early for them

By | February 27, 2014

If your social media friends are like mine you would have noticed a trend in increasing numbers of math problems being shared. I usually like solving and sometimes trying to solve these math problems. I mean, why not, they are fun.

The ones that I have come across recently especially in LinkedIn have been trap wired though. What I mean by that is that the problem is not what you think it is, or that they have laid out something front of you that captures your attention and stops you from seeing the knot. For example:


To get the result you would add the following number to the last result, right? 20+5=25, 25+6=31 and so on. So what about the answer? 38+9=47? Well it could be, if the rule was to add the last result to the next number. However, 8 is missing. So if the rule was to add the previous result to the next ascending number, to get the right answer you would have to first solve 38+8=46 and then 46+9=55 (Some could of course argue that 9=9, no matter what the numbers before it are). There are tons of these in the internet, if you like to exercise your brain a little. They usually follow the same pattern though, so it can get old quite fast.

However I recently ran into one that stood out from the crowd. Why? Because it seems very simple and logic, yet the answer can only be discovered by dumping the old way of thinking and approaching the problem from a completely different angle. On the video people are asked to work out the sequence and it’s interesting to see their reactions when the standard approach fails. The presenter interestingly references a book from Nassim Nicholas Taleb called The Black Swan, which became one of my favorite books along the predecessor Fooled by Randomness, when I was studying an MBA. Recommended reading.

Source: Veritasium

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