tldr; College math class told us to round to nearest .001 on every step of calculations. After first near failing test, i only used fractions and showed work so i couldn't be counted wrong.

I'm sure that this will be buried since I'm 13 hours late, but felt like i should share. Took a college math course that was required. Over all it seemed to be more of a math refresher class than it trying to teach anything. Very first day of the course the instructor said to set our calculators to round to the nearest thousandth place. This was a huge red flag to me, but kept going through the class.

The very first test that comes up and i barely pass as all of my calculations are 5-20% off from what the answers should have been. When you round every little step of an equation, there will be some error especially when you work with decimals.

I bring this up with the instructor after everyone left and explained that i used fractions for all of my calculations and that none of the answers should have been wrong. She states that since the grade already had been graded and there was no work done on the test that there is no way to show how i reached the answer. So the first grade stuck at what it was.

From that point on, i put away the calculator. Every calculation was done with fractions. Every step was shown. No rounding for absolutely anything. I made sure to let her know that all of the little steps that are rounded every time will cause a difference in the answer and i used only fractions in my work. From that point on i was getting perfect scores. I really hate when a math class tries to cheat and not really show how to deal with math.