An outstanding double prediction

The mentalist says: "I want everybody to take a trip down memory lane, to a happier time, remember your life at elementary school". The performer shows an envelope, he leaves it on plain sight and says to one spectator: "I want you to imagine that you are six years old, you are at school. The teacher is explaining simple math, she writes on the blackboard: 2 + 2 =. She asks you to write the result. You stand up, all your classmates are watching you, you take the chalk and you write the result. But you are so nervous that you don't write 4, you write a different number, a two digit number. I want you to write that number without anybody seeing you." The mentalist hands him a pad and pen. After he writes the number, he asks to tear down the page and keep it.

Then, the mentalist moves on to another spectator and reminisces about drawing on the blackboard during elementary school. The mentalist shows that the pad is filled with various drawings and asks the spectator to choose one without revealing it to anyone. The spectator looks at a drawing and imagines themselves drawing it with a piece of chalk.

The mentalist takes the envelope and asks the spectators to say, for the first time, what number and drawing they are thinking off. They say for example "43" and "a boat".

"Picasso said 'Everything you can imagine is real'", the performer takes out from the envelope, that was in plain sight the whole time, a slate and shows that has written precisely "2 + 2 = 43" and has a big drawing of a boat!