At first glance “assume” and “presume” seem very similar as they both mean to suppose something, however the latter is used only when we rely on some sort of evidence and although we cannot be 100% sure, the probability of our presumption is very high. Assume is used when we suppose something without evidence. For example:

If you want to learn something, ask and don’t assume.

If we assume that the process of creation of the Solar System involved a spinning disk of gas and dust that slowly condensed to form the Sun and the planets why was there so much more planet-building stuff in the orbit of Saturn compared to the orbit of Earth?

Mr Bond, I presume?

The missing person is presumed dead.