I can't speak for anyone else, but in my case at least, that's how it was taught. I remember the teacher going through problems on the chalkboard - "you want th

I can't speak for anyone else, but in my case at least, that's how it was taught. I remember the teacher going through problems on the chalkboard - "you want that brand new stereo for 150$ (This was the nineties) and you decide to put it on your credit card and then make the minimum payments. What's that stereo actually going to cost you?"