For those too young to remember d20’s numbered 1-10 twice, we used to ink the numbers on one side black and the other side red:
- When rolling for 1-20, the red side was +10 (e.g., red 5 = 15);
- When rolling for 1-10, ink color didn’t matter. (e.g., a black 9 or a red 9 were each just 9).
Nowadays, you can do the same using a d20 as a d10 by subtracting 10 from the double-digit faces (e.g., 11 is 1, 15 is 5, 20 is 10, etc.), or—better yet—by simply ignoring the 10s digit (e.g., 13 = 3, 16 = 6, etc.).
Yeah, yeah, old fart, I hear you thinking. But:
- We never mistakenly picked up a d10 for a d8 nor vice versa; and
- I can fit an extra set of polyhedral dice in my Tiny Gremlin brand dice tray! Think of how many extra sets that means in a dice bag!
As for all those unavoidable d10s in sets nowadays, you can reserve them for your Vampire: The Masquerade and other WoD RPGs. No need to buy a tube of WoD d10s!