ASSUME vs PRESUME is how they typically get mixed up. The difference is in the degree of certainty.
ASSUME and PRESUME both mean "suppose" which
To ASSUME is to make a guess based on little or no evidence. (That's why we have that catchy phrase about ASSUME.)
To PRESUME is to make an informed guess based on reasonable evidence or probability.
If someone walks past your house late at night, you might ASSUME (and hope!) it's just your next-door neighbor.
However, if your neighbor walks his dog at 11:00 each night, at 10:55 you can PRESUME he'll walk past in 5 minutes.
For example, "I just ASSUMED he would pay for the laptop he broke, but he never did."
For example, "The missing boaters were PRESUMED dead by rescue officials after searching for two weeks."
Memory trick: Presume = Probability
Assume = A lack of evidence
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