Math problems

My teenage daughter recently complained about learning math. But one day she will have to book airline tickets online, I told her, and differential equations might come in handy.

“Take this workshop that I’m attending in Dayton while you’re on spring break with your friend in Mexico,” I said. “What’s the cheapest way to get there?”

“Use frequent flyer miles,” she suggested.

I would. Except United doesn’t fly direct from Boston to anywhere in Ohio. And I’m not connecting through United’s Chicago hub during any month when snow could cancel flights. I would rather have a colonoscopy than sleep on an airline terminal floor.

So I logged onto Expedia. The cheapest flight to Dayton cost $101. But it leaves at 5 a.m.

We live three hours from Boston. So I would have to get up at midnight to make that flight, I reminded her. The last time I got up at midnight, I was in labor.

“Stay at that airport hotel,” she suggested, “the one where you can park for free.”

OK, I thought. Add $250 for the hotel. But subtract $150 saved on airport parking.

I toggled back to Expedia and clicked on the $101 flight. Session expired. I re-entered the destination and date information. The flight had gone up to $343.

In the old days, I told her, I would have called a travel agent, given her my travel dates, and she would have found the least expensive airfare. I then would have picked up the ticket — with its delicate carbon paper that stained fingertips and shirt cuffs murder-scene red — and paid the travel agent with a check. Once on board, smiling flight attendants would have passed out steaming towels with tongs, mixed free mini bottles of Seagram’s 7 with 7-Up or popped open some Cold Duck, and served at least one hot meal in a pre-molded tray, so the pasta primavera didn’t mix with the fruit cup in turbulence.

Now you practically need to do a statistical regression analysis to find the best deal online — and on an airline that doesn’t charge extra for the oxygen on board or have a coin slot on the toilet door.

Samoa Air even charges by weight. Your weight!

I finally found a flight leaving Boston at noon and clicked “select.” It connected through Atlanta and had gone up to $841. And something resembling a clown car rented for $30 a day. Plus $14.45 in taxes and fees.

“Now add it all up,” I told my daughter.

She looked at the list of numbers, then looked up and asked, “Can I buy a new bikini for Mexico?”