Number Sense: Is your child being taught to hate math?
© 2008 Gwen Dewar, Ph.D., all rights reserved
In his excellent book, The Number Sense, neuropsychologist
Stanislas Dehaene argues that kids go astray when teachers emphasize
calculation over conceptual understanding.
Left to their own
devices, kids discover strategies that make math meaningful.
Unfortunately, however, kids are often taught that these strategies are
At least, that's what happens in Western countries like
the United States and France--countries where students spend a lot of
time being drilled on the mechanics of calculation. Kids are chastised
for counting on their fingers because this is somehow viewed as
cheating. So are kids who use shortcut strategies to solve problems.
For example, Dehaene says, a child might solve the problem
By recalling that 6+6 =12 and that 7 is one more than 6. Ergo, 6+7 = 13.
Or, Dehaene says, consider this example from an experiment conducted by Jeffrey Bisanz.
Bisanz presented American 6 year olds and 9 year olds with this problem:
5 + 3 – 3 = ?
6-year olds tended to solve this without doing any calculations. They
just observed that the positive 3 and the negative 3 cancel each other
But the 9-year olds (who had learned from their teachers
what the "right" approach was) were more likely to take the long route
to the answer:
5 + 3 = 8
8 - 3 = 5
In other words, 9 year olds had learned that they should follow the teacher’s procedure first, and think later.
This reminds me of my own childhood, when I was learning
multiplication. What is 7 x 8? If I couldn’t remember, I’d add together a
string of seven 8s. Since I hated memorizing my timetables, I ended up
doing a lot of sums.
Hardly a clever shortcut, and it was prone
to error because I’d sometimes lose track. But I’ll say this for my
slow-poke approach: It helped me understand the meaning of
multiplication. It made things very concrete and intuitive.
According to Dehaene, one of the most common errors that kids make when presented with simple multiplication problem like
7 x 8 = ?
is to add the two numbers together:
7 x 8 = 15
what’s worse? Using the clumsy-but-meaningful strategy of adding up a
string of 8s, only to miscount and come up with 7 x 8 = 48?
Or misunderstanding the whole point and adding together 7 and 8?
favors meaning. When kids are trained to emphasize procedures over
meaning, they fail to develop an intuitive sense of number.
that leads to all kinds of trouble...confusion, boredom, a poorly
developed number sense, and (perhaps) a lifelong dislike of math.
Dehaene’s tips for making math intuitive
Dehaene argues that we can foster our children’s sense of quantity by
grounding mathematics knowledge in concrete, familiar situations. For instance,
when we teach our kids subtraction, we can present kids with the
concrete operation of removing apples from a basket.
And here are more recommendations from Dehaene:
• Let kids count on their fingers
• Teach kids about fractions by having them envision the division of a pie
• Teach kids about negative numbers by having kids think of temperatures.
Negative 5 may not mean much in the abstract...but how about 5 degrees below zero...?
Humans aren't the only ones with a bit of number sense, and even
human babies can perform certain mental calculations. For more
information, see my evidence-based guide to the
development of number sense.
In addition to highlights of the latest research, it includes more research-based for encouraging math skills in young children.
References: Number Sense
Dehaene S. 1997. The number sense: How the mind creates mathematics. New York: Oxford University Press.