To find how much less the temperature of dry ice is than room temperature, we need to subtract the temperature of dry ice from the temperature of room temperature.
The formula is:difference = room temperature - dry ice temperature
We can plug in the given values:
difference = 20°C - (-98°C)
We can simplify the expression by adding 98°C to both sides:
difference + 98°C = 20°C + 98°C
difference = 118°C
Therefore, the temperature of dry ice is 118°C less than room temperature.