Math 101

Equivalent fractions

2009-08-01T09:35:00.000-07:00

Sometimes, students just miss the difference between equivalent fractions and the square of them:

(porque means "because" in Spanish)

Just so you know, I'm maknig fun of students here, but I'm not picking on little, defenseless toddlers. Every entry in this blog comes from secondary students' exams. And they are all 13 or older. Anyway, you can still call me "mean bastard" if you want, but that won't stop you from laughing at the errors.

Sum of powers

2008-12-16T13:41:00.000-08:00

To begin this new era of mathematical incoherence, I present you with a classic: sum of powers

FYI, this guy got the best mark from his class in that test: 7.5/10 Sweet, sweet irony.

Comeback

2008-12-16T13:12:00.000-08:00

Originally, this blog was just an attempt to make some money online, and practice my english skills. Well, of course it also intended to entertain you with some of the best mistakes I have found on secondary school math tests.

But all in all, when the summer holidays were over, I kind of lost the interest on the blog and abandoned it. However, these last days, while I helped correct some tests, I was so amazed at the magnitude of the idiocies committed that I didn't know whether o laught or cry. Guess I'll just post them and let you decide!

So, here I am, back, and for good. Well, maybe not for good, but at least for a week or two.

Substraction

2007-10-21T08:57:00.000-07:00

I guess that that 6 is the result of doing 8-14, and then sticking the - sign up your butt, but I'm not sure really. I mean, is one supposed to pay attention to + and - signs?

Anyway, my favorite part of this image is the two-story number in the third line:
4
10

What in hell is it supposed to be? It's clearly not an exponent, because it's ON TOP of the 10, but then again, what IS it? I left that question to you boys.

Number Line

2007-10-05T19:03:00.000-07:00

If after the zero we write 1, 2, 3, 4, it is only logical to write the complete number line like this, right?

Now, I really don't know what bewilders me the most: the way in which this student draw the number the ifirst time, or the fact that the second time he did it, he wasn't disturbed by the fact that he had to completely ignore -5, -6 and -7 to make the new line.

Advanced equation solving II

2007-10-03T09:38:00.000-07:00

OK, let's go step by step:
1: How in earth can -4 -(-2) = -6 ??? Look! Even the minuses with the parenthesis look like a + sign! -4 + 2 = -2!!!!

2: This is probably one of my favorite errors. He decided to treat the numerator of the fraction as if it was completely alone!!! And he didn't stop there, either. He took the denominator and decided that it would be the numerator from there on. Speechless.

3: If anyone knows how a fraction whose numerator is smaller than its denominator , like 3/6, becomes greater than 1, please, let me know. I beg you.

Inequality

2007-10-01T16:23:00.000-07:00

I could give it a try and attempt to explain what this student tried to do... but I don't really think I could.

Again, this fella decided that the > sign was bothering him, and eliminated it. It's becoming a trend!

Simple arithmetics

2007-09-30T08:42:00.000-07:00

Don't you hate parenthesis in large calculus? The way in which you have to take care of not doing the operations in the wrong order? This student decided that he didn't care.

Hey! There's even a small smiley down there, ":-6"! And guess what there isn't down there? A result!

Cube roots and simplified fractions

2007-09-29T21:43:00.000-07:00

Anybody whith a minimal mathematical formation, even 10-year-olds, know that 4/8 = 1/2, and that 10/100 equals 1/10. Similarly, one tends to believe that the cube root of a number bigger than 1 is supposed to be smaller than that number.

Well, this guy doesn't

Now, for those of you who didn't already saw it, I'll point you to the end of the image, to see one of the greatest simplifications methods ever: dividing by 10_0 ! What? Did you never hear about it? It's the same as dividing by 100, but with a space in the middle! And it only affects the numbers you want, not necessarily the entire fraction! And what is more, you don't even have to bother to do the subtractions correctly! Just write 15-59=39, and you're done!

Advanced equation solving

2007-09-29T12:03:00.000-07:00

Most of us kow how to solve a 1st degree equation with only one variable. It's pretty simple, but it can be tedious. With this guy's method, we can "solve" it much faster:

How could we have been so blind for all this years? All we needed to do was to eliminate the = sign, and everything becomes much simpler!

...Although, what does "x 4" means? x=4? x=4x? x and 4 are friends and that's why they live together inside a badly drawn rectangle? I really don't know, but that's probably due to the high level of math knowledge that this equation method solving requires...