Just when I thought I was getting better at math...

[shadowkat]

This

Post by Power 95.3.

made me scratch my head.


7 + 7 divided by 7 +7 x7 -7.

The correct answer is apparently 50.

IF you do it this way: 7+7 =14 divided by 7 =2
2 +7 = 9, 9* 7 =63, 63-7 = 56.

If you do it by calculator = 56

If you do it by Excel = 50

Apparently it is supposed to be 7x7= 49 /7 = 1, then 1+7+7 -7 = 8.
Which still makes no sense. So, it must be = 7x7/7 =1, then 7+7+7 =21 +1
Still makes no sense. I remain puzzled.

This is why I hate math.

Comments

[cactuswatcher.livejournal.com]

Now that I think about it there was a discussion in Scientific American magazine, I think, about 20 years ago about some algebraic calculators which would give bad answers like this on chained operations. I guess that problem has not been eliminated completely.

[shadowkat67.livejournal.com]

Just tried it on my calculator - it won't wait for the next, or for me to enter an = sign. I plug in 7+7 and I get 14, before I even can press / by 7.
In order for it to work, I have to do this:

7/7 =1
7x7=49
1+7+49-7 =50

And I have to press "clear" really hard between calculations. But it's also a dirt cheap basic calculator provided by the government. Not a fancy one.