Answer: -25 degrees Celsius
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Explanation:
Draw a vertical number line. Plot -20 on it. Then move 5 units down to arrive at -25. Think of it as a thermometer where the temperature can be measured below 0 degrees, or you could think of it like floors of a building. Negative values would be basement floors.
The diagram below describes what's going on when we compute -20-5 = -25.
