It's worse when you look at how they explain it in the 2e PHB.Honestly, for many people, yes. Dyscalculia is a thing.
Also, it's simply not as fast as addition is, even when dealing with numbers as small as are likely to be found at a gaming table.
Here's a simple example: Rath has reached 7th level as a fighter. His THACO is 14 (found on Table 53), meaning he needs to roll a 14 or better to hit a character or creature of Armor Class 0. In combat, Rath, attacking an orc wearing chainmail (AC 6), needs to roll an 8 (14 -6 = 8) to hit the orc. An 8 or higher on Id20 will hit the orc. If Rath hits, he rolls the appropriate dice (see Table 44) to determine how much damage he inflicts.
Simple enough, right? Basic subtraction equation, maybe not as quick as addition for whatever reason but it's still straightforward. They then go on to give an example using modifiers..
Heres the same example, with some common modifiers thrown in: Ruth is still a 7thlevel fighter. He has a Strength of 18/80 (which gives him a +2 bonus to his attack roll). He fights with a long sword +l. His THACO is 14, modified to I2 by his Strength and to 11 by his weapon. If attacking the orc from the earlier example, Ruth would have to roll a 5 or higher on la20 in order to hit (I1 -6~5). Again, Table 44 would tell him how much damage he inflicts with his weapon (this information should also be written on his character sheet).
So a + to hit lowers my THAC0? Why wouldn't they explain a + to hit as just y'know adding to your roll?
