By now I have been playing bloons for a few years but I still cant understand how much health each bloon takes away. For example, a ceramic bloon takes away a little more than 100 health. But it only takes 18 hits (proved because snipers with the deadly presicion upgrade takes away 18 layers and one shot a ceramic). Why? What about a moab class bloon? You can't mesaure because they take away too much lives. What about fortified bloons? Do they take away double lives? Does anyone know?
The number of lives a bloon takes away is directly equal to the number of pops it takes to kill it. For example, a red bloon, which requires one hit to pop, deals one life worth of damage.
As a more general rule of thumb, imagine that the end of the track will pop each bloon that hits it, at the cost of one life. For example, let's say a black bloon makes it to the end of the track. You lose one life, popping the black layer, then two pink come out. They both pop, dealing one each, then two yellow bloons pop out. They pop, doing one damage a piece, and finishing with two greens. Same for blue and red. After all is said and done, you have taken 11 damage from that black bloon, even though the black bloon itself only did 1 damage, each of the ten remaining bloons the came out of it also did one damage, so you took 11 damage total. As you progress, it gets more and more complicated.
Zerbras dump a black and a white, meaning they do 23 damage, as 11 gets done from each of the black and white, and the zebra itself does 1 damage.
Rainbows dump two Zebras, dealing 47 damage
Ceramics dump two rainbows, but take 10 hits to pop themselves, dealing 47*2 + 10 = 104 damage.
MOABs have 200 health, and dump four ceramics, dealing 104*4 + 200 = 616 damage.
A more specific chart:
Red - 1 Blue - 2 Green - 3 Yellow - 4 Pink - 5 Black & White - 11 Zebra & Lead - 23 Rainbow - 47 Ceramic - 104 MOAB - 200+104*4 = 616 BFB - 700+616*4 = 3164 ZOMG - 4000 + 3164*4 = 16656
The other two worth mentioning are the DDT and the BAD. The DDT has 400 health, and dumps 4 camo regrow ceramics. This is just a MOAB+200, or 818, but it is much faster, and more difficult to damage. The BAD dumps 2 ZOMGS and 3 DDTs, and has 20,000 health for itself. 55760!
Camo - Most monkeys ignore these bloons, but they have no effect on the number of lives bloons deal
Regrow - Again, no life difference, but if left alone, can do quite a bit of damage. Keep in mind that a ceramic pops down to sixteen red bloons, and if it's regrow, each red bloon will grow back up to a ceramic, resulting in the duplification of many high level regrow baloons
Fortified - Everything doubles. Health, Damage, Number of hits to pop, but not speed.
If you want to test these out for yourself, go into "Sandbox" mode, unlocked upon beating a level. In sandbox mode, you set your life and money, cannot die, and can send any bloons in you want, against any monkeys you want. All of this information is on the bloons wiki, plus much more. I recommend you check it out: https://bloons.fandom.com/wiki/