Number of Digit after the coma depending on the value

Hello,

Here is my concern:
I wish to automatize the display of digit after the coma based on the value.
For instance if the result of a calculation made in a cell is: 9.8, I wish Excel to display 9.8 but if the value becomes higher than 100, I wish Excel to remove the digit after the coma. For instance if the result of a calculation is: 102.8, I wish Excel to round it and display 103.
Or it would be even more flexible if I could set a value, for instance 90 so that when the result of my calculation is above 90, it does not display the digit anymore.

Thank you for your help. This is a big issue for me.

Phil