A Hidden Value of Mental Math

March 17, 2015

I always advocate for elementary school math teachers to build strong fluency programs.  Automaticity with number facts builds students’ confidence and frees up brain space to concentrate on more complicated problems.  Just as practicing scales allows a pianist to one day compose music, strong math fundamentals provide a foundation for creativity and higher order thinking.

A few months ago, I learned the severe thought limitations that accompany weak mental math skills.


Kaitlyn, my 12 year-old niece, attends an affluent public school in suburban Philadelphia.  Language Arts is her favorite subject, but she always scores Advanced on standardized math tests.

A few months ago, Kaitlyn and I visited our Aunt Rhoda, the 95 year-old sister of my deceased grandmother.  The contrast between the youngest and oldest person in the room could not have been greater.  Aunt Rhoda grew up in a home without electricity and attended a one-room schoolhouse.  When we arrived, she was knitting and quietly singing a hymn.

Kaitlyn has grown up in a world of flat screen t.v.’s and social media.  She has an Instagram account and politely refrained from pulling out her IPhone during the 45-minute visit.

After we left, I told Kaitlyn that when I was her age, such a visit would’ve tried my patience, but over the years I learned to treasure talking with the elderly.  “Speaking to old people is the closest thing we’ll ever get to time travel,” I told her.

I then posed the question:  “If Aunt Rhoda had visited a 95 year-old woman when she was your age, in what year would that person have been born?”

Kaitlyn squinted as though her brain hurt.  She then looked up at me, waiting for me to give her the answer.

I was surprised.  An “Advanced” sixth grader, it seemed to me, should’ve had little trouble answering the question.  Still, I recognized that doing so required a lot of mental computation and this had never been Kaitlyn’s strength.

I was less concerned with my nieces’ mental math skills than I was her seeing the world of analogous situations.  I was posing the question through the lens of a loving uncle, not a tormented elementary mathematics teacher trainer.  Mental math was simply a vehicle to carry us into what I hoped would be a memorable conversation.

I tried again, this time giving her a simpler question.  “In what year would Aunt Rhoda have been your age?”

Again, she winced, this time surrendering to a stare more quickly.

I decided to give it one more try.  “In what year was Aunt Rhoda born?”  I didn’t see this question as being difficult at all.  If Aunt Rhoda were still living five years from now, she’d be 100.  2020 – 100 = 1920.

But by this point, my niece had given up and in doing so, she lost access to a deeper understanding of time and her relationship to historical events.


I gave in and told her that Aunt Rhoda was born in 1920 and that the visit we were just walking away from was analogous to a 1932 conversation between a 12 year-old Aunt Rhoda and a woman born in 1837.

Because she’s a sweetheart (far more like her mother than her uncle) Kaitlyn played along, doing her best to express deep thought through a slow, calculated head nod.

I wasn’t fooled.  Kaitlyn didn’t understand that Aunt Rhoda’s birth represented the midpoint between her own and a woman born in 1837.

Selfishly, I was a little frustrated, because Kaitlyn’s inability to do fairly simple arithmetic prevented us from having an engaging conversation.  But for her sake, I was sad, knowing that if her mental math skills were stronger, a frontier of thoughts would be readily accessible to her. 

One could argue that if she really cared about what I was asking, she would’ve pulled out her IPhone, accessed its calculator app, and performed the calculations needed to answer my questions.

I see it differently.

Had she been able to perform the calculations with little to no effort, she’d have had the mental energy to focus on the point I was trying to make instead of shutting down. 

If she weren’t intimidated by mental arithmetic, she would have had no trouble realizing that the oldest living generation has connected with people whose childhood pre-dated the civil war.

Realizing that we’re not that far removed from a drastically more oppressive society, Kaitlyn could’ve had better insight into many our nation’s social ills.  This, in turn, might’ve sparked deeper interests in history and current events.

A few fundamental math skills, mixed with her passion for reading and writing could offer vistas of learning she doesn’t know she possesses.

However, Kaitlyn is so limited by mental computational skills that many deep, wonderful thoughts might never enter her mind.  Instead, they’ll continue lying dormant in the recesses of her mind – her latent thinking capacity un-aroused.