The Paizo message boards allow for dice rolling. If you want to take an action away from the table, briefly describe what you are doing, provide the modifier (e.g., knowledge:arcana +6 ), and use the dice roller.
The tags for dice rolling below, but you should also be able to see it if you reply to this post.
The dice aren't rerolled when you edit a post. You have one hour after posting to edit.
Spoiler tags are useful if you want to pass private information.
Fort Save (-5)
1d20 - 5 ⇒ (17) - 5 = 12
Surprise Fireball!
6d6 ⇒ (2, 4, 6, 4, 2, 2) = 20