Tuzi_Cure said:

Let's say your player character has 10 HP.
I would multiply it by a factor of 10 for the display, so the player sees 100 HP. but as far as the code is concerned, it's still 10.
If the play takes 1 damage now, the player's HP should be 90 HP, then 80, 70, and so forth until 0 HP. In this case, the player may notice it's still a base 10 HP.
To avoid this, you may display the HP at an offset value of +/- some.

I would actually go in the other direction. It can be convenient to use floating point values for health and damage internally so that you can easily tweak the numbers in arbitrarily small increments. However, nobody except a certain type of math nerd wants to see more than one significant digit. It's immediately obvious that a weapon that deals 3 points of health is 50% more than 2 points of health, but it requires actual calculation to see that 27 points of health is 50% more than 18 points, and most people don't want to get out a calculator or spreadsheet to optimize their character.