Sunday, November 18, 2007

A mathematical riddle - think outside the box

My first good friend I ever got through the internet e-mailed me 2 days ago. He sent me a question I want to share. It is a good example of a problem where the solution is simple but to solve it you just have to change the way of thinking. Use both sides of your brain!

Use one straight line, horizontal, vertical or diagonal to make this statement valid:

5 + 5 + 5 = 550

I rule out the obvious one: a diagonal strike across the '=' changes the equation showing that the sides are not equal which of course is valid.
There are at least 3 other possible solutions I know of.


Black_Mamba said...

You have 3???? I can't even come up with one tsk tsk

Tanny said...

Ok, here is what I got

1) change the first + to 4:
2) change the second + to 4
3) change the = to "less than or equal to" sign

and you already ruled out the last one, do you have more solutions?

Leena Helttula said...

I did not rule that one out. I ruled out the "not equal" which I unfortunately can't type using the keyboard only. I am so used to mathematical editors ;)
Congratulations Tanny!

Jenny said...

Gee Whiz...I'm gonna have to take in my daily dose of caffeine and come back here a little maybe when my brilliant son gets up! lol!!

Anonymous said...

Put a diagnal line through the = and it means NOT equal