Within the harsh confines of Belle Reve, Ratcatcher tapped her fingers on her makeshift desk and clamped down on a well-worn pencil between her teeth. After painfully deliberating, she decided to choose "C.) All of the above." And with that, she held out the paper in front of her with pride and let out a sigh of relief.
Having grown up in the sewers of Gotham and raised by an ex-exterminator distrustful of almost all of those who lived above and didn't have tails, she had not enjoyed a conventional education by any means. As such, she never got the opportunity to enjoy the benefits of what a high school education had to offer.
But having her prison sentence almost come to a close after serving her country's interests via several missions on Task Force X had given Ratcatcher perspective. There was a whole world full of possibilities out there now, an opportunity to do something better with the skills she had honed after years of bottom-dwelling.
The past few months of learning math in particular was a major revelation for the rodent-themed supervillain. Everything seemed so straightforward, only right and wrong answers. So unlike her own life, spent either in absolute darkness at worst and at best operating within shades of gray.
As a matter of fact, Ratcatcher had been wanting to test a theory for a long time she had read about in meme forums, but decided to save it for after the test. After all, she needed all the luck she could get. But now the time had come to discover, once and for all, that dividing something by zero would actually result in terrible misfortune.
On her scratch paper (decorated absentmindedly with cutesy doodles of mice) Ratcatcher proceeded to write out the following: 21/0=
Arthur Light of Earth. RISE.
The very moment her pencil left the pad of paper, the reanimated supervillain Doctor Light burst into her cell, sporting a Black Lantern Ring and a truly greasy goatee. A giant mousetrap composed entirely of ebony energy surrounded Ratcatcher and snapped down on her torso.
As Ratcatcher felt the metal dig into her ribs, she saw several bullets travel through Doctor Light's chest and head. The zombie crumpled to the ground, jaw sagging. Her teammate, Blackguard, was standing over the two of them, twin guns smoking and wearing an expression of pity.
"Ah, nuts, Ratatouille… You never divide by zero. I told ya that." He shook his head regretfully.
"My bad." Ratcatcher sighed. "Dying is still better than summer school, though."