It has not escaped my attention that not everyone is as fast as arithmetic as I am. Adding two numbers together can take time. The play of the current edition of *Dungeons & Dragons* isn’t as bad for this as 3E (where adding 17 and 24 together wasn’t that unusual at the higher levels).

Combat in D&D often plays like this:

“I attack and roll an 8… add 5… Does a 13 hit?”

“Yes. How much damage?”

“4 plus 3 is 7, plus 4… 11 damage!”

Once you have a fighter with multiple attacks and the player isn’t that good with numbers… things can slow down significantly, creating frustration to other players at the table. How, then, to improve the speed?

Well, you can use average damage (as the monsters do in the *Monster Manual*). This works, but it is often not very satisfying. Rolling damage is one of the high points of the fighter’s play.

However, you can also improve the speed of combat by changing the way you determine if an attack hits.

The trick is that if you know the monster’s AC – and there’s rarely a reason the DM won’t tell you – you can quickly work out the number the die needs to roll. So, if you have an Attack Bonus of +5 and you’re attacking a Armour Class of 13, you need to roll an 8 or higher on the die. (Target Number = Armour Class – Attack Bonus). Once you know that number, you don’t have to look it up again. Just remember it. “I need an 8 to hit the goblin.” Thus, the exchange becomes:

“I attack and roll an 8! Hit! Damage is 4 plus 3 is 7, plus 4… 11 damage!”

Calculating what you need to roll on the die rather than rolling the die and then doing the calculation is quicker.

Another method you can use is to pre-calculate the target numbers. This method dates from the original days of D&D. Draw up a grid, and label the tops of the columns with the ACs from 10 to 20. Then, for each weapon, work out the number you need to roll to hit those ACs and put them in the cells below.

Thus, for a fighter with a Longsword with a +5 attack bonus and a Longbow with a +2 attack bonus, we get:

Then, in combat, the DM tells the player the goblins have an AC of 13. Looking on the table, it’s simple to determine that the longsword needs an 8 on the die, and the longbow needs a 11 on the die.

Players who are quick with numbers don’t need this technique, but remembering what the target number is tends to speed up combat significantly.

That table reminds me a lot of the AD&D 2e THAC0 tables. This could possibly be called a THAC20.

You’ll find the tables used in AD&D 1E fit it more; the THAC0 was an attempt to get away from the table look-up and towards calculation. But calculation takes time, which is why it’s sometimes better to precalculate!

Pingback: DwD&D#85 – What’s New in D&D Jan 31st » Misdirected Mark

Funny, but I was looking at the other side of the calculations. I am DMing my two kids 11 and 9, and their friends. Part of the joy as a parent was making them do all the calculations. It was slow at first, but within a few sessions they were getting faster and faster. It also helped with their math in school.

(I’m a college professor though, so I was using it as a learning opportunity) 🙂