“Sure! I’d  love to have you demo a lesson!” Ms. B’s eyes widened as a smile grew on her face. I was surprised and thankful that she was so open to the idea.

“Great!” I replied. “What unit are you doing right now?”

“Well, we just finished Quadratics and we’re about to start Volume and Surface Area.” Ms. B replied, pointing to the standards list on her wall.

“Okay, so how about I introduce Circumference and Area of circles?”

“That’s fine. What do you need for that?” Ms. B asked, ever eager to help.

“Do you have graph paper, calculators, rulers, that sort of thing?” I asked.

“Calculators? You let your students use calculators?” Ms. B countered, incredulous.

"You what?"

“You what?”

Yes, I do let my students use calculators.

Here’s why:

Lifelong Need

My wife doesn’t know her times tables. She’s a university professor and will regularly grade freshman Theology papers sitting on the couch. She’ll call out while I’m cooking or playing with the baby.

“What’s eight times six?”
“What’s 27 plus 18?”
“What’s 85 divided by 15?”

I'm a walking, smiling, calculator in the Vaudrey household.

Husband: a walking, smiling, calculator

When I’m not home, she has a calculator in her pocket all the time. Even if her phone is in the other room, she can Google it.

My wife doesn’t need computational skills.


…but she needs the reasoning.

She needs to know what the average means, when to find the sum of a row and give the total student points, and how to explain to her college freshmen what it means to have 6 quizzes, each worth 10% of their grade.

"But what if I miss one? Can I still get a C?"

“But what if I miss one? Can I still get a C?”

The students in Ms. B’s classroom also have calculators in their pockets. I want them to know how to use it effectively, which is a much better use of their time than memorizing their 12s tables.

Diane Kinch, former president of CMC and board member of TODOS, gave this truth bomb at a recent workshop:

Students have had 15 years to learn their times tables and they still don’t know them. At a certain point, I have to stop boring them, give them a calculator, and say “Let’s do some math”.

In my own classroom, we use TI-83+ calculators nearly every day, which I like for a few reasons:

  • TI-83s keep a record of the last 8 or 10 calculations, so if students clear accidentally, they can recall it.
  • There are tons of other buttons that do weird math stuff that we won’t use this year. This (f0r some) serves to build creativity about what’s coming next. About 2/3 of the students found the Stats Generator application and did coin-flipping trials four months before our unit on probability.
  • They could easily show their neighbor the order of steps and describe the reasoning that led them there.

Let’s work backwards


Students who focus on reasoning instead of computation are better prepared for college and career in the US.

(It’s notable that most of the grunt work for my CPA buddy’s tax clients comes from the western coast of peninsular India. Computation is a high value there.)

That’s why I use calculators in the classroom all the time; because I think that reasoning is more important than computation.

For more on that idea, watch this by Dan Pink.

~Matt “Which one is the minus sign?” Vaudrey