"What the actual fuck?"

It was a low mutter from the brunette across the table that caught Oliver's attention. He glanced up from his book and studied her in the reflection of the train's window.

The reflection allowed him to look without being overtly weird.

She was hunched over a piece of paper with a pencil in her mouth. In her right hand, she held a large pink rubber that hovered over the piece of paper. She groaned, then furiously rubbed out whatever she had written.

Curious, Oliver looked around and tried to get a closer look at the sheet. He could just make out the title: Long Division.

He frowned. Why was a woman in her twenties doing long division?

"This is what calculators were invented for," she hissed.

Normally, Oliver would not speak up. He would not interfere. He would return to his book and drown this woman's mutterings out.

But he was curious.

"Excuse me, do you want some help?"

The woman looked up and glared at him with such ferocity that he sat back a little.

"I used to sit on the top table in Maths when I was a kid, but I can't do it now! Why is long division so hard?"

Oliver's first thought was that this woman was very emotive about maths.

"Might I ask when the last time you did long division was? Before today, that is?"

"Uh…" She paused to think, her face screwing up a little. "Damn. Maybe like ten— Twelve years? I think we covered it at GCSE? Wow, that was a long time ago." She sighed. "Sorry, it's just I was good at Maths and I did a science degree, I should be able to do this. I need to help my nephew…" She rubbed her forehead and continued. "I can remember short division…"

"Your nephew required maths tutoring?" Oliver asked.

"Oh no, quite the opposite. He's eight, normally they don't learn this stuff until they're like ten or eleven. But he's a bright kid and the teacher is really good about it. She knows he's keen and wants to keep him that way. But this is the first thing he's struggled with and I'm Auntie Mai with the science degree and I should be able to help but…" She sighed again. "Normally I would google it but I have no signal on this train."

"That is very kind of you."

"Sorry, I'm disturbing you now."

"It's fine." Oliver placed his bookmark between the pages of his book and returned it to his bag. "Let me have a look."

"You do maths?"

"I do theoretical physics, so yes, I guess I do."

The woman — did she say her name was Mai? — slid the piece of paper over.

"I suppose I am desperate enough to ask for help from a physicist…"

Oliver raised an eyebrow at her.

"Don't tell me you're a sociologist or something."

He smirked, scientists putting down other disciplines was a form of banter he was familiar and comfortable with.

"Eww, no. I did chemistry at university and then did a Master's in Forensics. That's why I was in London, I was giving evidence in court…"

"Chemistry is applied physics…" Oliver muttered under his breath as he read the maths sheet. "Can I borrow your pencil?"

Mai handed it over.

Oliver read the first question and began scribbling. He handed it back a moment later.

"There."

Mai checked it over.

"How the hell did you do that? Don't tell me you use long division in your job?"

"No, I, like you, have not done it in quite a while…"

"Then—"

"I have a very good memory."

Mai smiled.

"Can you show me exactly how you did that?"

"Of course…"

Oliver proceeded to explain the second question, allowing Mai to write some notes as he did so.

"You're a good teacher," she said once he was done.

"I lecture a little," Oliver said. "I've had practice."

Mai frowned.

"As in lecture at university?" she asked. Oliver nodded. "How old are you? If you don't mind me asking."

"Twenty-eight."

"What the fuck."

"I graduated early."

Mai opened her mouth to speak, but the tannoy cut her off.

"The next station is—"

"Fuck this is my stop," Mai said, gathering her things together. "Thank you so much for your help. I really appreciate it."

She hurried from her seat towards the door. Oliver packed up his own things and followed. As the train doors open, he saw Mai disappear off through the crowd of commuters. Oliver set off at a slower pace. Gene was supposed to pick him up from the station but he would, no doubt, be late. It was also raining. He smiled to himself, glad he had helped someone.

Author's note: So I found this in my WIP folder and was like "I can't add to this?" so I thought I'd publish as is? So... Yeah?