Mental-jaunt #2 (February 4, 2014)
jaunt (noun) a short excursion or journey for pleasure
mental-jaunt (noun) a short mental excursion or mental journey for pleasure, nothing too heavy!
Mental-jaunts are trails that will evoke certain ways of thinking that are very helpful both in understanding more complex mathematical concepts as well as life in general.
One person’s thinking along one possible trail is supplied to assist you in taking your students on the trail.
In a very old book on my shelf it says:
Pick any three digits from 1 through 9 and write them down as a three-digit number. Let’s call them a, b and c.
For example if I chose 538, then a=5, b=3 and c=8. Now run through the following chain on your calculator:
a X 2 + 3 X 5 + b X 10 + c – 150
The answer will be the three digit number you wrote down.
a) Try this out. I did, and it did not work for me, did it work for you?
b) If not, assuming there is a typographical error or two, can you correct this?
c) If not, assuming there is no typographical error, what is going on?
d) Share the mental-jaunt you went on with someone – explaining what you were thinking at the very start and how you reached your destination.