Will somebody please explain unit stats to me.

[City Builder]

Could somebody be so kind as to explain unit stats to me in the image above.

Honestly, I'm sure there is a strategy here but all I'm really doing is tossing my minions at my enemies but I'm thinking that perhaps if I knew how the stats, attack, defense, damage actually worked then I might get more out of it than feeling like I'm simply tossing minions at the enemy.

For example, on the bear in the photo above, what does the 1 represent and what does the 4 represent? On my Griffon, what does the 1 represent and what does the - represent?

When I attack and it tells me 81-101 damage (but 0 kills) does this mean that if the unit stack is let's say 2, then my attack will inflict 81 to 101 damage on one of the units in that 2 unit stack only?

Thanks,