Mutually exclusive events cannot both happen. Add their probabilities. Do not also multiply as if they overlapped. Independent events can both happen, in independent events.
Or versus and
Rolling a 1 or a 2 on one die: 1/6 + 1/6. Drawing a red card and a face card can overlap, so those are not exclusive. Combinations count the groups behind some of these items, in the combinations formula.
Two-way tables are another place “or” shows up, in two-way tables. The short list is in ACT Math formulas.
The bottom line
Cannot both happen: add. Can both happen: do not treat them as exclusive.
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