When a Combined Skill Roll (p. 55 of the 7th ed. Call of Cthulhu Rulebook) is appropriate, the Keeper will state “Roll against (Skill A) and (Skill B).” This means you roll once and compare your result with both Skills, and are successful as long as your result is equal to or under both, or simply one of them as the Keeper requires.
If only one is required and you have History at 45% and Archeology at 50% and you roll a 48%, you succeed because your result is equal to or under your 50% in Archeology.
I also apply this to rolls against both a Skill and an Ability Score.
My name is CthulhuBob Lovely, I live in my childhood hometown of Columbus, Ohio, and have a son and two daughters. I volunteer at MisCon, which occurs each year on Memorial Day Weekend in Missoula, Montana and help out at other shows.
In my younger years I had seen H.P. Lovecraft’s books in the collection of my older brother, Brian, who is also responsible for introducing me to Monty Python, Star Wars and many other things geek.
I began running and playing Dungeons and Dragons in 1977 at the age of 15, and Call of Cthulhu since its original publication in 1981.
I believe geekery and gaming can have positive effects on math, reading and writing, and social interaction skills, as well as family togetherness. I have three published stories online at