When is it OK to round decimals and when is it not?

Hello,

So in most problems I encounter, rounding to the second decimal place in my work produces a good enough answer.

However, I just did a computation where rounding caused a significant difference. Solving for an interest rate in the TVM function on the BA II made a huge difference when I made an input of a rounded number for FV.

So is a there a general rule of thumb of when to round and when to not?


When is it OK to round decimals and when is it not?