[yequalsx]

I teach mathematics at a community college and I can tell you that for most people the mathematics on the test is hard. Our course with the largest number of students is on arithmetic and the students just don't comprehend fractions. They can't even comprehend how to convert a decimal to a percent. Especially when given a problem like:

Conver 0.25% to a decimal. That really throws them off.

[watchandwait]

I've heard from folks in retail finance that large segments of American society do not understand the concept of an interest rate. Everything is just "what is my monthly payment?"

[yequalsx]

After a lecture and doing several examples I a majority of my college algebra students couldn't do this problem.

You have a house that you bought for $120,000. You sell the house for $173,000 and the real estate commission is 6%. As the seller of the house you have to pay the real estate commission. The real estate commission is an expense and is not counted as part of your profit from the sale of the house. You have to pay a tax of 30% on the profit from the sale of the house. How much tax is paid?

They just couldn't grasp that the real estate commission was not part of their profit. I got the impression that the students believe that the real estate commission is not an expense.

I do believe that a large percentage of society does not understand interest.

[mattdeboard]

I talked to a fellow CS major Thursday evening and he said he hated all the math involved with the CS program, and that he' failed Pre-Calculus & Trigonometry I three times. This came out after he was complaining about his discrete computational structures class being "nothing but proofs".

If you don't like the math, why get a CS degree? Get a physical science degree and learn how to code on your own time.

[rflrob]

Physical science probably won't be much better if you don't like math. Remember, "The book of nature is written in the language of mathematics". Heck, be a humanities major and learn to code, it's not like computers only work for people with technical degrees (though I suspect the training in rigorous thinking helps).

[brettnak]

While I understand this question, I think it is a bit of a trick. I think it would make more sense to ask them to convert 1.25% to a decimal, or any percentage that did not have leading zeros.

[yequalsx]

I think it is important for one to be able to follow instructions even if they might appear counterintuitive. The rule for conversion is to divide by 100. It doesn't matter what percentage I give you; always divide by 100. It's fairly straightforward but many people are unable to do so in the case of 0.25%. They expect the answer to be 25.

[mattdeboard]

It's not a trick. It requires critical thinking skills, and that a student internalizes concepts like percentages, decimals and fractions.