Why do Children with ADHD Often Have Trouble With Math?

As a clinician who has evaluated hundreds of children with ADHD, as well as having a son with ADHD, I noticed over the years that these children often struggle with math skills in school.   A scientific study, done in 2015 which reviewed several previous studies, concluded that there is a strong association with ADHD symptoms and poor math skills, especially for those children diagnosed with ADHD, Inattentive subtype. 

What is it about learning math skills that is so difficult for ADHD children?  Is there some deficit in these children’s native ability to understand quantitative information or what some experts call “number sense?”  If so, this would be a true learning disability called “dyscalculia.”  Or is it something else?

Based on what we know from research in neuroscience, we can say that it is something else.  Let’s look for a minute at a typical math problem for fourth and fifth graders:  457 x 83.  In order to calculate the result by hand, we convert it to this format 

457

X 83

Then, in order to solve this problem by hand, one has to go through 22 steps in correct sequence, as well as have the time tables memorized.  If we multiple a 3 digit number by another 3 digit number, say, 457 X 283, we have to work our way through a total of 31 steps perfectly.

What are the skills involved here?

1. First of all, these challenging problems involves what we call “working memory.”  This refers to the capacity to hold information in one’s mind--while engaging in other steps-- long enough to then use the information.  We use working memory when we are engaging in mental math.  At the gas pump, we are using working memory when we are thinking, “Gas is $3.19 a gallon, and my car holds 11 gallons, so a fill up is going to cost me $31.90 plus $3.19 which will equal about $35.00.”  Research has consistently shown that children and adults with ADHD have limited working memory.  They might be able to do one or two operations with small numbers, but not the 22 step operation above.  Think of working memory as like a container.  Some of us are blessed with big containers, and we can hold lots of data in it, and keep it circulating for a pretty long time, where others have small containers with holes in them.  The information goes in and quickly leaks out.

2. A second skill needed to solve the math problem above is “internal speech”.  This refers to the capacity to literally talk to ourselves internally in order to guide our actions.  In order to solve the math problem above, a child would have to begin with speech like this, “OK, where do I start?  Oh, I remember I have to start with the problem on the far right of the second row, the 3.  I have to multiply the 3 by the number directly above it, the 7.  What is 3 times 7?  I remember, it is 21  Then I have to put down the 1 and carry the 2 to the number next to the 7, the .”  There is a lot of internal speech that is necessary to work this problem. 
   
   Studies show that children begin to adopt internal speech to guide their actions as early as four years of age.  Ex.  “I need to be still and pay attention during story time, or I will have to leave the circle and sit at the table at the back of the room, so I’m going to try real hard to be still.”  Children with ADHD are developmentally slow at developing internal speech.  This accounts for their impulsivity.  They react immediately to their environment without using their internal speech to regulate their emotions, control their body movements, suppress their tendency to blurt out, etc.

3. Attention, concentration, and memorization.  It takes deep concentration (I know it did for me) to stay focused on a math problem through 22 or 31 consecutive steps.  A child has to memorize all the times tables, retrieve them from long-term memory, memorize the steps to be used for two and three digit multiplication problems, retrieve them from memory—all while not getting sidetracked, not going off task midway through the problem, but seeing it through all the way to the final answer.

I recall afternoons when my son had to work such problems.  It went something like this.  “OK, where do I start?  I start with the 3.  I do 3 times 7.  What’s the answer?  I don’t remember.  Is it 28?  35?  I’ll have to start with 1 times 8 and work my way up.  Ok, that’s 8.  What’s 8 times 2?  Uh, uh, this is a cool miniature skateboard.  I can make a ramp with this salt shaker turned sideways, and zoom it off the ramp. Oh no, now the salt is coming out.  I’ll scoop it onto the floor.  Oh no, the dog is licking it…”

Putting this altogether, we can see the skills that are needed to be a strong student in math—good attention and concentration, the ability to stay on task and not get distracted, well-developed internal speech or verbal skills, and strong working memory.  All of these skills are problematic for children with ADHD.  They will need a coach/tutor/parent to help them with complex math problems in order to stay focused, to stay on task.  They will need a quiet space with no distractions.  The coach will need to guide the child through the sequence of steps correctly, calling them out, cueing and prompting the child, step by step. 

Children with ADHD can learn complicated math, of course, but they may need more drill, more repetition to internalize those steps.  When doing math homework after school, they may benefit from a second booster dose of medication to maximize their attention span.  Parents can use routine errands  like grocery shopping to give their child opportunities to practice mental math.  Ex.  “Yogurt cups are 4 for $5.00.  How much does one yogurt cup cost?”  Or cooking.  “The recipe calls for a ½ cup of sugar for 6 servings, but we want to make half that much, so how much sugar should we use?” 

References

(1)   Anobile, G.  2022.  Math difficulties in attention deficit hyperactivity disorder do not originate from the visual number sense.  Frontiers of Human Neuroscience, 16, 949391

(2)   Greven, C.  2014.  Evidence for a Shared Genetic Risk Between ADHD Symptoms and Reduced Mathematical Ability.  Journal of Child Psychology and Psychiatry, 55 (1), 39-48l

(3)   Tosto, M., et al.  2015, Aug. 27.  A systematic review of ADHD and mathematical ability.  BMC, 13, 204.