By the Grace of the Gods (Manga) 05

Slime's up for one recently deceased middle-aged businessman! When the gods reincarnate him in another world as a boy with magical powers, he discovers that magically-tamed slime are an untapped natural resource!

Now that the fantasy of being transported to another world has become his new reality, it's up to former office worker Ryoma to figure out how he wants to make his way in this brand-new world!
 
His days are packed with advising acquaintances, exterminating goblins, and planning his new business! The pace of his life might be slower than the one he was living on Earth, but Ryoma has more than enough to keep him busy!