During the 1991-92 school year, my newsletter, "Trotter Math" News, carried a special feature: its own advice column. It was called "DEAR ADDY". And here is how things went for that year...

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[August 1991]

No, that didn't say "Dear Abby"; it said "Dear Addy".
(ADDY for addition, the first number operation one learns in
elementary school.)  So, here is your advice column, for those
of you who have a "math problem", and would like to have profes-
sional help.  Send your letters to Mr. Trotter, and I'll try to
answer them.  You may submit them anonymously if you wish.  But,
please no homework problems.  (I wouldn't be able to reply in
time anyway to do much good.  Ha!)

Here's our first letter---

My teacher says it would be a good idea to
use the "Indiana Method" in multiplying numbers.
But I don't remember what it's all about.  Can you
help?

Molly Multiply

Dear Molly,

Yes, I've heard of the "Indiana Method"; it's a
good idea.  Let's use an example:

So you see the Indiana style just sets the extra
zeros off to the side, and brings them down before
multiplying by the remaining digits.  It saves time and
space, and is lots neater, don't you agree?

[September 1991]

My teacher says he wants to see all my scratchwork
on my homework and tests.  And even more he wants it neatly
done.  I don't think he's being fair; I don't want to be
bothered.  What do you say?

Scratchy Sam

Dear Scratchy,

I understand that many people don't want others
to see their scratchwork.  Perhaps they feel bad that they
couldn't do some calculations in their head, for example.
But I think your teacher just wants you to be more careful
in all your work.  Afterall, you should do everything
possible to maximize your grade on a test.  If you work
carelessly (this often means sloppily) and rapidly, you
will often miss a problem that you might have done cor-
rectly with a little more care.  Remember the old saying:
"Haste makes waste."
Also if you leave your scratchwork, your teacher
can analyze your mistakes more easily in order to help
you.  And don't forget that maybe he'll give you some
partial credit for trying!

[October 1991]

I have been having a lot of trouble lately
with long division.  I keep getting wrong answers
on my homework and tests (see one of my examples
below).  Can you help me?

Dizzy Divider

Dear Dizzy,

Yes, I can see you are making a common error
that also many of your friends are making.  (So you
are not alone.)  Look at your example and compare it
with the correct way:

You see, you are merely placing your remainder in the
quotient as a "decimal".  There are three basic ways to give
a division's answer: with remainder, mixed number, and decimal.
I gave the mixed number form above; the other two for that
problem are "8 r3" and "8.75".

The trouble is that you are confusing the "remainder"
form with the "decimal" one.  Each form has its best use time.
If your problem was "How many 4-person relay teams could be
formed with 35 runners?", the remainder style says "8 teams,
with 3 runners left over".  But, if you were asked to share 35
candy bars among 4 persons, the mixed number style (8 3/4) is
the best way to give the answer.  The decimal style is more
often used in scientific areas or similar measurements.

My advice: when it's "just a plain division" problem, use
the mixed number form.  (Here's wishing you "dandy dividing".)

[November 1991]

I hate fractions!  I just never get the right
answers on my tests.  Like the other day, I had this
one: 3/4 + 5/8.  My answer (8/12) was marked wrong,
even after I reduced it to 2/3.  Can you help me?

Fed Up with Fractions

Dear Fed Up,

Most of your trouble lies, I feel, in the fact that you	don't
understand there are two kinds of fractions: the parts-of-a-whole
kind and the ratio kind.  Your teacher gave you a problemof the
first kind, which is usually what is meant on most tests if there
is no information to the contrary.  So you have to do it by changing
the fractions to the same denominator before doing any adding.  In
your problem this would be 6/8 + 5/8 = 11/8 or 1 3/8.

Ironically, your problem WAS done right, that is if it were
a ratio type problem.  Observe: 3/4 and 5/8 could have meant that a
baseball player had 3 hits in 4 times at bat in the first game, and
then went "5 for 8" in the 2nd game.  This means he then had 8 hits
in 12 times at bat, which is a "2 out of 3" ratio.  [I guess this
means we could call such fractions "baseball fractions", right?]
Try to find other real-world situations for which this method of
adding "fractions" makes sense; then you will understand the whole
idea of adding fractions much better.

[December 1991]

My math teacher used some unusual words the
other day when talking about subtracting polynomials
in Algebra.  He said something like "min-you-end" and
"sub-truh-hend".  What's this all about?

Min Sub

Dear Min,

Your teacher was using the technical terminology for the
two main numbers in a subtraction problem: minuend and subtrahend.
In the expression "8 - 4", 8 is the minuend and 4 is the subtrahend.
This reminds Addy of a poem I saw in an old Algebra book. It says:

Mary, Mary, quite contrary,
How do your polynomials subtract?
Change the signs in the subtrahend,
And add, as a matter of fact!

Memorize this and it will help you a lot.

[January 1992]

I'm confused about the difference between
"rational" and "irrational" numbers.  It all seems
"nonsensical" to me.  Can you help?

Irate Irrational

Dear Ira,

The simplest meaning for "rational number" is that it is a
number that can be expressed in fraction form.  This is because the
root word in rational is "ratio", and ratios are often written as a
fraction.

Obviously then all fractions are rational.  But so are all
whole numbers.  For example, 3 has these fraction forms: 3/1, 12/4,
and many more, of course.  Even so-called decimals can be rational,
that is, if they are terminating ones like 0.75 (which is the same
as 3/4) or repeating ones like

1
0.142857 142857...  = ---
7

Now to the other type.  Somewhat as in everyday life,
"irrational" means "not rational".  Therefore, an irrational
number should be one that cannot be expressed as a ratio of
two whole numbers, or in other words, as a fraction.  Perhaps
the easiest way to see this is with the square root of a number
like 10.  In trying to find a fraction which when multiplied by
itself produces 10 exactly, none can be found.  You can get very
close with certain fractions, e.g. the square of 19/6 is 10 1/36.
This is why we say the "square root of 10 is irrational".

[Decimally speaking, these will be numbers whose decimal
forms do not stop or repeat a certain group of digits.]

[February 1992]

What's this thing called "MATHCOUNTS" all about?
I didn't go to the Saturday morning competition last month.
Did I miss anything important?

Missed It All

Dear Missed,

Yes, I'm you missed a big event last month (Jan. 25).
Sixty-four students showed up at the Primary Cafetorium, and
sixty were 8th graders like you.  Everybody seemed to have a
good time, too.

The basic competition consisted of two parts: a 30-problem
test called the "Sprint" round, and an 8-problem test called the
"Target" round.  Each Sprint item is worth 1 point and each Target
item has a 2-point value.  The points on each part are combined to
give one's final score.  The winners and their scores in the two 8th

ALGEBRA I:
1. Desiree Cuenca (19); 2. Dave Lamborn (15); 3. Yaron
Gilaei (13).

PRE-ALGEBRA:
1. Gabriela Nasser (13); 2. Karla Wyld (10, S=8);
3. Claudia Ramirez, Cecilia Rivas, Claudia Vallejos (a 3-way
tie at 10, S=6).  [Note: ties are broken by how many Sprint

One of the tougher problems on the Sprint section was:
How many two-digit numbers are there whose digits have a sum that
is a perfect square?  If you can do it now, show me your work as
proof and I'll give you some bonus points.  OK?

[March 1992]

I get confused between the terms "square" and
"square root".  I always say one when I should say the
other.  Can you straighten me out?

Mixed up on squares

Dear Mixed,

This is a most important topic you've asked about.  Squares
and their "roots" are used a lot in physics and engineering, not to
mention mathematics in general.  Put as simply as I know how, the
"square of a number" is the product obtained by multiplying a number
by itself, e.g. 16 is a square because 16 = 4 × 4.  And the "square
root of a number" is that other number which when multiplied by itself
produces the original, given number.  In this latter case, 7 would be
the square root of 49 because 7 × 7 = 49.

We often speak of perfect squares as those whole numbers that
are squares of other whole numbers (positive integers): 1, 4, 9, 16,
25,....  In one sense of the word, they have "perfect" (integral) roots:
1, 2, 3, 4, 5, ...  All other positive integers do not have such "nice"
roots.  For example, 10 is not the product of a whole number times itself;
you can only use such approximate decimals as 3.162 or mixed numbers
like 3 1/6, in order to "come close to 10" by squaring.

[April 1992]

I'm having lots of trouble with word problems in
my math class lately.  I just hate them.  They make no
sense sometimes.  Why do we gotta do them?

Weary of Word Problems

Dear Weary,

I understand your frustration, really I do.  For years and
years now students just like you have been grappling with word (or
story) problems.  Traveling from Town A to Town B at r miles per
hour, fathers twice as old as sons, mixtures of peanuts and cashews
and other such ideas have been around for a long time.  Basically they
are supposed to train you in logical thinking skills so that you will
be better able to solve the "real life" problems that you'll face
later on.

I know they are hard to solve, but my first advice is to read
the problem very carefully, even slowly, and read it more than once if
necessary.  Few people really know what they should do by reading it
only one time.  Pay close attention to what it asks you to find.  Most
of all, though, remember that you will never become good at solving them
by avoiding them.  It gets easier the more that you eventually do.  Keep
trying.

[May 1992]

Addy wants to celebrate the end of the school year in a
"lighter" vein; no serious advice this time, ok?  So here's one
of my favorite math jokes:

Once upon a time in an Indian village, there lived
three squaws.  They had the strange custom of sitting
around on certain animal hides.  One squaw spread a
bear hide near a pine grove; the second squaw carefully
laid a moose hide in the shade of a large oak tree; and
the third squaw placed a hippopotamus hide beside a
rippling brook.
The first two squaws would pass away their time
happily playing with their sons, while the third squaw,
who was still childless, had to sit quite alone, waiting
for her time to come.  As it just so happened, the two
boys each weighed 50 pounds, while the single squaw
had a weight of one hundred pounds.
To this day mathematicians give credit to these women
for proving the Pythagorean Theorem, because you see:
The squaw of the hippopotamus is equal to the sons of the
squaws of the other two hides."

(Addy says: "Have a good summer vacation!")

1. (Aug. '91) Multiplication: Product Dates, CDP's, Five Distinct Digits,
Double/Triple, 9 Digits Equal Products, Same Digits Multiplication,
More Strange Multiplication
1. (Oct. '91) Division: Divisibility Tests, Rep-digit Numbers, Trotter Dates
2. (Nov. '91) Fractions: Fraction Addition, Fraction R.O., Repeating Decimals
3. (Feb. '92) MATHCOUNTS: MATHCOUNTS
4. (Mar. '92) Squares: Square World, Square Multiplication, DDS's,
Seeing Double, Happy & Dizzy Nos., Primes & Square Pairs,
Single Square Sums, "Math" Price Is Right
5. (Apr. '92) Word Problems: Problem Solving Guide
6. (May '92) Pythagorean Theorem: Pythagoras 1980, Pythagorean Triples,
Phone Number "Lengths", Word "Lengths"

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