Fancy yourself a math whiz? (in Off-topic)

Below is one question from the Pennsylvania standardized test for the sixth grade, reproduced exactly from the copy of the question I was given:

78(25 [] 9) = 78 [] 20 [] 78 [] 5 - 78 [] 9

Complete the equation by filling each box with the symbol for addition, subtraction, multiplication or division.

Can you solve the problem that made at least one of my mother's students cry?

78(25 + 9)=78 * 20 + 78 * 5 + 78 * 9.

78(25-9)=78*20+78*5-78*9?

78(25-9) = 78x20 + 78x5 - 78x9

all you have to do is look at all the 78s

The problem, JS, is that the second-last operation is subtraction, not an open box.

78 (25 - 9) = 78 * 20 + 78 * 5 - 78 * 9

Oh, whoops. Silly mistake, but easily fixable.

And Obscurans wins!

I know it wasn't a hard question, I just found it funny that some kid actually started crying over it. Hehe.

If you're looking for something a tad harder, there's always this geometry question.

78 ( 25 - 9) = 78 x 20 + 78 x 5 - 78 x 9

Eyes on your own paper, Lammie!

Solution to Triangle Problem 1:

Rule, sum of all angles in a triangle equals 180 degrees.

1. Triangle AB(bisection). Angle of bisection is 50 degrees. Due to angle congruency, the opposite side is also 50 degrees.
2. Triangle ABE. Angle E here is 30 degrees.
3. Triangle BDE. Angle D = 180 - 20 - 30 + x, thus D = 120 + x.
4. Triangle DE(bisection). Sum of all angles equals 180 degrees. Thus 120 + x + x + 50 = 180. 170 + 2x = 180.
5. x = 5 degrees.

Did I make a mistake anywhere?

You messed up in step 3, twice:

First of all: 180 - 20 - 30 = 150
Second of all, it should be - x, not + x

So now you solution goes:
3. Angle D = 180 - 20 - 30 - x, thus D = 130 - x
this will give you step 4:
4. 130 - x + x + 50 = 180, thus 180 = 180 (shocker!)

Please try again. :D

Correction to my previous correction:

First of all: 180 - 20 - 30 = 130

I really wish there was a way to edit posts... even if only for a few minutes after posting.

Angle E is 30 + x, not 30 - x.

Angle E is 30 + x, but, look at what you are trying to do:

Triangle BDE.
Angle D = 180 - Angle B - Angle E
Angle D = 180 - 20 - (30 + x)
Angle D = 180 - 20 - 30 - x
thus D = 130 - x.

Nobody reads the hints, do they ?
You CAN'T solve it without making some "additional constructs" on the figure.
You always end up with a "180 = [...] + x - x" kind of thing otherwise.

I read the hints, tried to solve it for about an hour, then Googled the answer and realized that I didn't want to spend the time trying to go through the answer as it is really, really long.