Doctor Brun was at it for years, but he'd finally got his time machine up and running. His first trip was to a time way back in the past when dinosaurs roamed the Earth. To his surprise, the dinosaurs were actually quite intelligent. His first encounter was with Timmy Rex (a Tyrannosaurus Rex). They began talking about philosophy and politics. Eventually, mathematics came up. Here's the part of the conversation they had, including some of the cave writings.
Doc Brun: Ok. Just to be sure we understand each other, can you complete these equations for me?
Doc Brun wrote $1 + 2 =$
T. Rex wrote $3$
Doc Brun: Great. And this one?
Doc Brun wrote $12 \times 3 =$
T. Rex wrote $102$
Doc Brun: What? That's not right at all. Let's try another. I think I see what's going on here. Is this equation right?
Doc Brun wrote $1 + 3 = 4$
T. Rex: I don't even understand what you wrote there!
Doc Brun: I see, just as I thought. I'm assuming that--
The frustrated T. Rex hastily ate Doc Brun in one bite.
What was Doc Brun going to say before he was swallowed?