Blocking with First Strike + Deathtouch
107.1a You can’t choose a fractional number, deal fractional damage, gain fractional life, and so on. If a spell or ability could generate a fractional number, the spell or ability will tell you whether to round up or down.


Normally, you must pick an integer number of damage. So in a normal game, a 6/8 Hundred Handed One with First Strike and Deathtouch only kills 6 of the blockers. The remaining four 3/3 survive to deal 12 damage to Hundred Handed One, killing it.

In an Unhinged/Unglued game, 107.1a is modified.


  For right now (and I reserve the right to change this with future Un sets), whenever you choose a number, if that number is written as p/q in lowest terms, q must be 1 or 2. If you stopped taking math in high school, for any fraction the greatest legal denominator is 2. And if you've mentally repressed all math-related knowledge, the only fraction you can choose is {1/2} (and yes, 1{1/2}, 2{1/2}, etc. is fair game).
  
  Does this mean that while playing silver-bordered cards I can break up Pyrotechnics to deal {1/2} damage to eight creatures (trust me, I can come up with a reason)?
  
  Yes. Yes, you can.


Hundred Handed One can now deal 1/2 damage to 12 creatures. In a Unhinged/Unglued game, and only in such a game, HHO will survive the scenario unscathed. It would take 15 3/3 attackers to kill HHO.