This is a beautiful teaser contributed by Pooja Singh, who tried this with her 9 year old. So will encourage everyone to try this, it could be a nice, 5-minute puzzle!
You begin with the number 458. You are only allowed two operations, each of which can be repeated any number of times:
– You can multiply the number by 2
– Remove the last digit, i.e. the one in the unit’s place (e.g. 8 in the number 458)
Your task is to get to the number 14, beginning with 458. Do this in the minimum number of steps.
As always, please send your answers as comments within the blog (preferred), or send an e-mail to email@example.com. Please do share the puzzle with others if you like, and please also send puzzles that you have come across that you think I can share in this blog.
Happy number crunching!