Cheryl arrived for our lesson on the back of her boyfriend's Harley. My student and her ride were almost twice my age, I figured, but perhaps their weathered exteriors fooled me. I forget his name. He only sniffed around inside long enough to decide that I had no designs on his woman, never removing the patriotic handkerchief from his head. The presence of my wife and daughter appeared to do the trick, sending him off on undefined errands.

My only student at the time, Cheryl had entered college after twenty years or so as a fruit picker. Told me she wanted to teach kindergarten. Why the state required a course in algebra, although she would never have to teach it in an elementary classroom, was the question that plagued her existence. Her first attempt to pass had been a dismal failure. She hired me to help her through the second time. Six sessions in half as many weeks failed to improve her prospects, although I had tried several different strategies.

"You're a slave driver, Jack," her gravel churning voice complained, although her expression was more playful than serious.

I exhaled long and deep. "Really, I'd love to talk about the Red Scare, but if you're going to pass that test on Tuesday we have to do the math." She was a master of avoidance strategies.

"Okay, okay. I'm focused," she assured me. In order to be more convincing, she shifted her package of Kool cigarettes and disposable lighter to one side of the table, an evident distraction. "I'm so glad you're helping me get through this so I can graduate. I tell everybody what an angel you are."

"Thanks." It would not have surprised me in the least if she really had sung my praises to all of her friends, despite any measurable progress. She had proven generous, always trying to give me more money than I requested, always thankful as if I have been helping her out of the goodness of my heart. Indeed, if temperament was the only prerequisite, she would be great with the little ones. But at times I suspected delirium tremens.

I wrote the square root of 125 on a dry erase board and slid it in front of her. "How would you simplify this?"

She chewed nonexistent fingernails, her mascara outlined eyes cautious, like a raccoon on a dumpster. "You factor the number, right?"

"Great. You can do this," I said. "Go ahead."

Reassured, she took the marker, positioned it between her thumb and fingertips, drew three lines with the steady, deliberate manner of a demolitions expert, then stopped.

I watched the dust illuminated by the glare over her shoulder, wondering how long I should wait before giving her the next step.

"Jack," she wondered aloud, "have you ever seen a big foot?"

Uncertain if I had understood the question, I replied, "You mean . . . the sasquatch?" I had not heard of one mentioned in years. But then, I don't read the tabloids as often, since I no longer take care of the grocery shopping.

"Yes, that's it."

I shook my head. "Afraid not. I always thought they were a myth."

Cheryl's jaw dropped and eyes widened in disbelief. She pushed her chair away from the table and planted her hands on her knees. "You don't believe in the big foot, Jack? But they got pictures!"

"Probably a guy in a costume," I stated. Then I realized she had done it again. Angry with myself, I attempted a flanking movement. "Now, what do you know about the number . . ."

"Really, Jack? You think so?"

Facing defeat, I sat back, exhaled all the stale, frustrated air, and swiped the thin strands of hair from my forehead. I thought it over, scratching my chin so that it was obvious. Cheryl waited, alert and anxious, as if I was Moses preparing to lay down the law, as if her entire belief structure depended upon my response. I knew better, however, recalling the enormous effort required to convince her that Ted Turner didn't colorize The Wizard of Oz.

"Well, what do I know? They could exist," I began. "Let's suppose, as an example, that they caught a hundred twenty-five of those big-foots and divided them evenly into five rows. How many would you have in each row?"

Cheryl reached out and patted my arm, but then began to concentrate when she saw that I was serious.

"Twenty-five," she suggested. When I nodded, she popped out of her chair, more excited than I had ever seen her before. "Oh, Jack. I think I get it!"

Now if I can somehow illuminate the mysteries of the square root with the bat boy and two-step equations using crop circles, she just might pass.