Base damage: -10
num of dice: 10
sides per dice: 11
base damage: -1
num of dice: 1
sides per dice: 101
or one of many other combinations.
Both cobinations give you 0 - 100 damage. The difference is how the probabilities of different damage values are distributed.
If you have the combination with only 1 dice, then each damage (1, 2, 3, ... 100) has the same probability.
However if you use more than one dice the damage values close to the mean value (50) have a higher probability assigned than values closer to the tails (1 and 100). The more dice you have the bigger the difference of the probability of 50 and 1 or 100.
If you want a "more random feeling", go for fewer dice.
If you want mostly damage around 40-60 and sometimes a very low or high value, then use more dice.