A 5-Step Approach to Problem-Solving
1. Draw pictures (geometric, graphic, maps, etc.), clarify definitions, use
abstraction, and estimate answers.
Step 1 of the CCM approach is to “make sense of problems.”
Drawing a picture is a good way to begin to solve a problem. Then, we can place
symbols (abstractions) on our drawing to allow us to write formulas or
equations. Step 1 of my general approach is to “learn the definitions.” This is
also essential to problem solving.
Estimation can improve our accuracy and alert us to
significant errors. For example, at the end of our restaurant dinner, we
estimate that four dinners, two glasses of wine, and two desserts should cost
us about $80. If we receive a bill for $220, either there has been a
miscalculation, or we were handed the wrong bill. In any event, we will want to
review the bidding to find the cause of the discrepancy.
Measurement can be fun. How big is the soccer field at the
park? One way to estimate that is to “pace off” the distances. Suppose that
your daughter measures the width of her soccer field at 80 paces. How wide is
the field? That depends, doesn’t it, on the length of her pace. If a single
pace is about 2 feet 6 inches, the answer is… At this point, we recognize the
value of terms of approximation such as about,
almost, approximately, around, just over,
just under, etc.
2. To really learn something, teach someone else
Step 3 of the CCM approach suggests sharing ideas with
others. I agree that that learning should be a cooperative – rather than a
competitive – endeavor. At first glance this may appear to be altruistic, even
self-defeating – why should your son invest valuable time to help another
student with whom he may be competing for grades. The answer is that to
actually help another student, your child must learn the material well enough
to teach it. Showing his fellow student how to solve a problem and then
answering questions about it strengthens your child’s understanding. As a
tutor, your child learns as much as or more than his fellow student. There is
no need or expectation that the favor be returned for the tutor to receive full
benefit. By the way, this is what so-called “group math” can be when members of
the group teach each other.
Moreover, the competitive aspect of learning is an artifact
of school rules, such as, “do your own work.” In “the real world,” knowledge
that your child gains is an asset whether or not a colleague also learns it,
however the act of teaching increases the probability that such knowledge will
be real.
Likewise, at homework time, your child can receive almost
identical benefit by teaching you, especially if the definitions, concepts, or
problems are new to you. This is a subtle but effective way for you to help
your child to exercise a growth mindset
to break through a new area, an area that you may or may not be familiar with.
One test of this learning process is whether you are able to understand his
explanations; for that, you need to be awake and focused. One benefit of this
process is that teaching becomes a valuable tool in his learning-to-learn
toolbox.
3. Invest time to learn but learn how much time to invest
Fidelity in doing assignments, such as reading the next
day’s lesson or solving homework problems, is important. However, I am cautious
regarding the emphasis on perseverance in CCM Standard 1. I recommend that you
and your child establish a regular time to do homework and a limit on the
amount of time to do it. The more time spent on math homework, the less time
will be available for other things. Variety is not just “the spice of life,” it
is the key to developing multiple capabilities.
It does require some confidence to get past the idea that
all homework must be done completely and correctly. Homework is a teaching
tool, so using it efficiently is to your child’s advantage for at least three
reasons.
There are limits on how much time she can focus
on after-school homework; beyond that limit, we are wasting her precious time
and energy.
Knowing that the time to finish her homework is
limited, her focus and productivity will improve.
And, incomplete homework also has value,
especially in math, because it often reveals strengths and weaknesses.
The third point requires her to assume some responsibility.
With time running out to complete the homework, she should read any problems
not yet attempted. Then, she should write down her questions about the “problem
problems.” During the next class, having thought about these problems, she will
find the answers to her questions valuable because those hard problems will
become solvable problems.
This recommendation is about setting priorities and taking
responsibility for those priorities. Not finishing homework is a reflection the
amount and level difficulty of assignments and the time available to complete them.
Learning to appreciate both the costs and benefits of spending that time wisely
is part of learning to learn.
4. Avoid “getting stuck”
Why? Isn’t perseverance an admirable quality, a character
trait necessary to success? Not getting stuck is not the same thing as giving
up; it simply means that after investing a “reasonable” amount of time to solve
a problem and getting nowhere, I may be missing something critical. Ordinarily,
if I cannot find my car keys, I have misplaced them. However, on occasion, if I
cannot find my car keys it’s because someone borrowed them and failed to put
them back. This is something I can only find out by asking. If that is the
case, continuing to look in more and more unlikely places will only waste my
time.
While perseverance is part of being an effective learner, as
was just pointed out (in recommendation 3), effective use of time is also
important. As was also just pointed out, homework not only offers an
opportunity to practice solving problems, it can reveal what we do not
understand. This is valuable information, because it shows where we need to
strengthen our knowledge and problem-solving skills.
Here are three things your son can do when he cannot solve a
homework problem:
First, ask someone else, a fellow student, a
sibling, or you. Even if you are not the one he asks, you can help him learn to
ask for help. For example, his older sister may be right person to help him,
but some parental oversight may be necessary, at least at first, to assure that
help is requested and given in a climate of mutual respect. That may mean suggesting
to younger brother that he be ready to explain where he is stuck and what he
does not understand. It may also mean suggesting to older sister that her role
is to help him to get past the point where he is stuck rather than to solve the
problem for him.
Second, some texts offer the possibility of
looking up the answer in the back of the book. It takes some ingenuity to use
such an answer and then to work backwards. This should not be the usual
procedure, because it reduces the value of that answer as a check on the
original work; nevertheless, it is a better option than getting stuck.
Third, the process of formulating a good
question for the teacher can be helpful since it requires an awareness of where
misunderstanding has occurred. At times, composing the question will lead to a
redefining the problem, getting “un-stuck,” and finding the solution.
Some parents, especially those whose children are struggling
with math, are tempted by after-school tutoring. For example, the question may
be “to Kumon™ or not to Kumon?” I say that, unless all else has failed, “no.”
The “drill-baby-drill” approach to math is not my idea of how to ignite or
maintain enthusiasm for math in your daughter. If you want to extend the limit
on the time to do homework, that’s okay as long she – not you – is proposing
that. But to subject her to solving hundreds of problems in order to improve
test scores is rarely a good investment of time; Kumon is drilling and may or
may not promote critical thinking. She has enough math during the school day
and in her after-school homework. Better to use the time to work on her
two-hand backhand, practice for her guitar lesson, or jog around the lake with her
friends.
5. Verify that answers are reasonable and work backwards to verify
solutions
Whether on homework, a test, or on the job, we want our
calculations to yield correct answers. Unfortunately, since we are all human,
we will sometimes make errors. Therefore, we need to check our answers; the
more techniques we have to do this, the more likely it is that we will find and
correct errors.
For example, having two ways to perform subtraction, the old
borrow-when-necessary approach and the new regrouping, our offspring should be
able to fix their subtraction errors when they occur. Learning which operations
are complementary, such as add/subtract, multiply/divide, and sine/cosine is
useful.
Approximation is a tried and true approach to detecting
errors in orders of magnitude. Before solving a problem, I can estimate the
answer. For example, if 7 students are sick in a class of 150, I estimate that
this is between 4% and 5%. When I divide the number of sick students (7) by the
class size (150), using a calculator, I get 0.047. According to my estimate,
that answer isn’t even close. However, the % sign means percent (per 100), so I
need to multiply my result by 100. The calculator was correct, but I failed to
enter all the necessary data. Fortunately, my estimate alerted me to my error –
the correct answer is 4.7%.
Finally, memorization is generally our friend. Once we
understand the theory behind an operation, memorization can be a great
convenience. I have seen grocery cashiers who have memorized the code for
practically every item in their store; this is a great time saver for them and
for their fellow cashiers at customer checkout time when item barcodes are
missing. Likewise, your child should know the multiplication tables and use
that knowledge whenever convenient. There are many opportunities to memorize
useful formulas and operational results (once their meaning is clear).
No comments:
Post a Comment