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People are not good at statistics. We tend to imagine more or less than 100% chance when dividing it between possibilities. Instead, try this:
If theres something certain to happen but less certain when, imagine a row of a calendar (or however you visualize sequential days) with different amounts of paint on certain days. Maybe its likely in the next few days but a small chance it could take a few weeks. So spread the paint in those proportions. Its always 1.0 total paint. For uncertainty, leave some of the paint blurred and you dont know where it is. As the days pass and the thing still hasnt happened, you move that chance somewhere onto the later days since its still 100% going to happen.
Or if it may not happen, use 2 colors of paint, 1 for all relevant possibilities, and an inner paint touching only part of that outer paint. If its 30% chance to happen, the inner paint touches 30% of the outer paint.
Recursively, we can think about combinations of events, places, things, and chances this way.