I could see she was really concentrating: her lips were moving slightly. Then she tried to write on a sheet of paper, but her writing was going all over the place, up, down, zigzagging like a roller coaster, a real arithmetic big dipper. What with her staring eyes and her jumbled handwriting, she was going to get caught out on the first day, or at least raise serious suspicions. The teacher began to hobble between the desks, still weighed down by her dead baby. A dead child is surprisingly heavy, especially when you have to carry it around all the time. I realized she was going to see Marie’s haphazard writing, so quick as lightning I grabbed the paper from her and put it down on the desk in front of me. As the teacher reached my desk, everyone looked at me. I held the paper out to her.

“Here’s the answer,” I said confidently. “It’s very badly written but I think it’s right.”

“Yes, it’s right, but why is it such a horrible mess?”

My brain went into overdrive and this is what came out.

“It’s because of the passion…”

“The passion?”

“Mathematical passion. An intense feeling: like an instinct. The same phenomenon has often been observed with poetry and music.”

I looked her straight in the eye. Boldly saying the first thing that comes into your head is often the best way out of a tricky situation. She didn’t quite know how to respond and Marie created a diversion by offering to give the answer to the whole class.

“A = 3(x + 1) + (x + 2)(x – 3). Therefore A = 3x + 3 + x2 – 3x + 2x – 6 = x2 + 2x – 3.”

I was completely astonished, because she’d pulled that out of nowhere with nothing to cling on to except the trapeze of her intelligence and her memory. How pathetic I was in comparison. While all the others were scrabbling to put away their things, Marie leant casually towards me and whispered, “Walk in front of me to clear my way through. Don’t go too far ahead, I’m still not very good at getting my bearings. Try to stamp your feet a bit so that I don’t lose the thread…”

Her face twisted in a wretched smile. As we made our way along the corridors, I stamped my feet like a flamenco dancer. Van Gogh, still with a piece of sticking plaster on his ear, said as he passed by, “Hey, did you go to Spain for the holidays?”

But I didn’t want to stoop to his level, so I simply told him he was a mug. He said I was a mug too, but I was ready for that and came straight back with, “You’re so full of it, you’ve got to be the biggest mug of all.”

I don’t know why, but this retort shuts them up every time. It’s quite something.