Math at the Cafe with Ruby

You show up to one of the campus cafes early in the afternoon, grabbing a table by the long glass windows. The sunshine feels great on your face, and it soon illuminates a bright smile on Ruby’s face as she pops in a minute later. She’s wearing a grey sports bra and yoga pants, workout clothes that also happen to look damn good with her full figure.

She catches you looking, because she touches her chest, saying: “I’m going to the gym after this. I didn’t feel like changing over there.”

“I don’t mind the decision one bit,” you smile. “Are you getting a coffee?”

“Tea,” Ruby says. “It’s better for the body! You should order one next time.”

“It’s not my cup of tea,” you say, and she gives you a flat look, her mouth twitching in almost amusement.

“Well, really, it’s too hot for me,” you laugh, lifting your cup of cold brew. “Unlike something, or somebody else…”

“That’s another reason why I didn’t want to change over there,” Ruby says to you with a wink.

She comes back a couple minutes later with a cup of steaming tea, the small label hanging off the tea bag indicating that it’s chamomile.

“I like it’s soothing effects,” she says, taking a sip. “It’s also good for focus! Perfect for studying for this math class. You should give it a try sometime!”

“You’re really pitching this like a MLM momtrepreneur,” you say, chuckling. “But I guess that’s why people fall for them, because I’m persuaded. Can I have a taste?”

“Be my guest,” she says, pushing the tea towards you.

You take a sip from the paper cup, and almost drop it.

“Hot!” you exclaim, passing the tea back to her. “I think I burned my tongue… need something to cool it off...”

You stare at Ruby’s lips. {if Ruby > 50} She meets your gaze by leaning over the table and plants a quick, wet kiss on your lips. {endif}

{if Ruby > 50} “Did that help?” she smiles. {else} “Drink your cold brew,” she laughs. “That’ll help.” {endif}

{if Ruby < 51} You take a big gulp of your coffee, swirling the chilled liquid in your mouth, and then swallow it with a small gulp. {endif}

“Much better,” you smile. “You come up with the best ideas.”

“That’s only because we haven’t started on the math yet,” Ruby laughs. She pulls out the latest problems that Luck assigned, and splays them out over the coffee table.

The two of you take a moment to scan over the first problem.

“Is this even true?” you wonder aloud, frowning at the equation.

“Luck wouldn’t give us a trick question,” Ruby says, although she too looks mildly puzzled by the question. “Isn’t it annoying that there’s a floor function in the numerator? What do I do with that?”

“No idea,” you say, shaking your head. But then, you pause: “Maybe we could decompose it? Into a sum?”

“Talk to me,” Ruby says, interested in what you have to say.

“Well, in some sense we could just take the sum of the integrals from x to x+1, right? And then the floor function practically writes itself—”

“It’s just the n, or the index, whatever we use to sum,” Ruby quickly nods, sketching out the equality.

“This isn’t a hard integral to evaluate,” you say, pointing to the thing inside the sum that she’s written.

She nods, writing it out, muttering: “Oh, and here the s cancels! This is working!”

“But this is basically it, right?” you say, getting excited and staring at the sum. “Because if we expand the term…”

“It telescopes,” Ruby laughs, not quite believing herself, and then she pauses. “Oh wait, oh no, it doesn’t quite collapse…”

“Each group cancels to 1/n!” you interject, using your pen to resketch the brackets around the terms she’s drawn.

“Yes! That’s it,” she says, excited. “That gives the solution!”

She grabs your arm and gives you {if Ruby > 50}another{else}a{endif} quick kiss, over before you can even react to it.

“Wow,” you mutter, touching your lips. “That really got you fired up, huh?”

“It’s just so pretty,” she laughs. “Here, I want to write it out neatly. That way I won’t make a fool of myself in class.”

“You math people find the strangest things beautiful,” you chuckle. “But hey, if it gets me kisses, I’m not complaining.”

“There’s still a dozen more problems to prepare before next class,” Ruby says, taking a drink from her tea. “That’s a lot of kisses!”

“Again, not complaining,” you smile.

Ruby +20