Does deathtouch and trample together let you assign just 1 damage to each blocker and trample the rest?

Normally, trample requires you to assign at least enough damage to a blocker to be lethal (its toughness minus any already-marked damage) before you can assign excess damage to the defending player. Deathtouch changes what counts as 'lethal damage': any amount of damage dealt by a source with deathtouch is lethal (CR 702.2b).

Because of this interaction (explicitly confirmed in CR 702.19b), when a creature has both trample and deathtouch, assigning just 1 damage to each blocker satisfies the 'lethal damage' requirement. All remaining damage can then be assigned to the defending player or planeswalker.

This applies to each blocker individually. If two creatures are blocking, you must assign at least 1 damage to each of them, and you may then assign the rest to the player.

Example: Your 10/10 trampler with deathtouch is blocked by two 5/5s. You assign 1 damage to each blocker (1+1=2 total), then assign the remaining 8 damage to the defending player. Both blockers will die to deathtouch, and the player takes 8.

This is one of the most powerful combat keyword combinations in the game, and the rules explicitly support it. Citation: CR 702.2b (deathtouch lethal damage definition) and CR 702.19b (trample lethal damage assignment).